Let’s say for the sake of argument that the NBA trade deadline passes on March 15 without the Celtics making a major move. Under that very plausible scenario, they would move forward with their aging core for presumably one last playoff stand. Who knows? Maybe they channel both the 1999 lockout Knicks and their own not-so-distant history by blazing an unexpected path to redemption through the postseason.

That last part may be unlikely, but the chances of team president Danny Ainge standing pat at the deadline rank at least even with pulling off a major move. What then?

As everyone knows, the Celtics will have enough salary cap space to pursue a max free agent with money left over. As everyone also knows, the chances of landing Dwight Howard fall somewhere between slim and none, which leaves Ainge in a quandary.

Does he use that new-found space to pursue lesser free agents or trades and try to stay competitive, or does he hold tight and wait for bigger names to become available down the line? The answer lies somewhere in between. In both his public comments and his actions, Ainge understands that the fastest way to irrelevancy is blowing through cap space on middling free agents. That doesn’t mean, however, that he will just wait for a savior to become available.

The Celtics’ rebuilding process is likely to take several years and will require patience and planning. Here is a highly speculative look at how it would look:

WHAT WOULD BE LEFT

The Celtics have four players under contract for next season: Rajon Rondo, Paul Pierce, Avery Bradley and JaJuan Johnson. Brandon Bass has a player option for $4.25 million, which is a bargain for a player of his caliber, meaning he’ll likely opt out.

They also have an option on E’Twaun Moore and can make a qualifying offer for Greg Stiemsma, who have both flashed NBA ability and have the advantage of being extremely affordable. Assuming they retain both players, their cap situation looks like this:

Committed salaries with Bass: $35.52 million

Without Bass: $31.27 million

Expected salary cap for 2012-13 season: $58 million (Note: The cap is set after the season, but for the purposes of this exercise, the $58 million figure will do.)

It’s important to remember that the Celtics’ cap space is theoretical. The eight free agents, plus assorted other blasts from the past represent over $95 million in “cap holds.” (See Sham Sports salary page for details).

In order to use that space one of two things have to happen. Either the free agent player signs with another team, or the player’s rights are renounced.

It’s possible that say, Kevin Garnett or Ray Allen could be re-signed for significantly less money. It’s also likely that some players such as Mickael Pietrus or Chris Wilcox may be re-signed. Either way, it would be a surprise if all eight pending free agents had different addresses next season.

(The others: Jermaine O’Neal, Marquis Daniels, Sasha Pavlovic and Keyon Dooling).

THE DRAFT

Barring a complete collapse from the Clippers, the Celtics will have two first round draft picks: Their own and one from the Clips via the Kendrick Perkins trade. While that Clippers pick may not carry the promise of a lottery windfall like it once did, having two picks in what should be a loaded draft is a definite help in the rebuilding process.

The Celtics would have the 15th and 23rd picks in the draft at the moment. Per Draft Express, the 15th-rated prospect is none other than Duke freshman guard Austin Rivers and the 23rd rated prospect is North Carolina freshman forward James McAdoo. Obviously a lot will change between now and the draft, but even picking in the middle and latter part of the first round should yield quality options.

WHAT THE ROSTER MIGHT LOOK LIKE

PG: Rondo, Bradley, Moore
SG: Pietrus*
SF: Pierce, Jeff Green*
PF: Wilcox/Bass*, Johnson
C: Stiemsma

* Anticipated signing

We’ve gone ahead and slotted Pietrus, a returning Jeff Green and either Wilcox or Bass with the two first rounders on a theoretical roster, giving the Celtics 11 players for about $45 million. (Again, that’s very rough estimate).

That’s not enough for a max player, but if Howard goes elsewhere, as expected, there’s no one else besides Nets guard Deron Williams who is worth that kind of money. That’s still plenty of space to add players who can be part of the rebuilding project. The key is not breaking the bank and keeping their options open beyond next summer.

THE FREE AGENT MARKET

The obvious needs are at center and the shooting guard position. The free agent market may be thin in unrestricted free agents but there will be a larger-than normal influx of restricted free agents and they offer some intriguing possibilities.

Centers: Roy Hibbert, JaVale McGee, Brook Lopez, Robin Lopez, Omer Asik
Forwards: Ryan Anderson, Nic Batum, Mareese Speights, Michael Beasley, J.J. Hickson, Jason Thompson
Guards: O.J. Mayo, Eric Gordon, George Hill, Rudy Fernandez

SIGN-AND-TRADES

Garnett and Allen are the key figures here. It’s not out of the question that one or both could return at a reduced salary, but if they decide to go elsewhere, the Celtics could use them in sign-and-trade scenarios that could yield either players or trade exceptions for future use.

Remember, they used the sign-and-trade route to acquire Bass and turned a trade exception for Daniels into Dooling. Everything is an asset in the NBA, including expiring contracts.

TRADES

One of the benefits to having cap space is it allows you to absorb contracts without having to match salary in return. That opens the door to limitless possibilities for Ainge to wheel and deal. Teams below the luxury tax line can also take back 150 percent of player contracts in trades as opposed to 125 for taxpaying teams.

Additionally, Bradley, Johnson and Moore are getting important playing time. All three were unknowns before the season started, and while none of them may be cornerstone players that have more value now than they did when the season began. Add in two more first rounders and Ainge is in a position to begin stockpiling assets for a future move.

LUXURY TAX ADVANTAGES

It’s also worth pointing out that teams below the luxury tax threshold (about $70 million in salaries) have certain advantages, such as access to the bi-annual free agent exception (worth just under $2 million) and either the room exception ($2.5 million) or the non-taxpayer mid-level exception worth $5 million. In December, the Celtics could only offer the taxpayer mid-level worth $3 million.

It gets complicated in a hurry, but the larger point is that the Celtics would go from a tax-strapped, over-the-cap team to one with several new options and possibilities virtually overnight. All of that is why retaining flexibility is so important for the Celtics as they look to rebuild and why Ainge won’t trade his core players just to make a move.

The Celtics came into Monday’s game with the Mavericks having lost three straight and five of six. It was also the second night of a back-to-back on the road and the next one of those they win will be the first.

Brandon Bass is out with knee problems. Kevin Garnett is away from the team and dealing with a family issue, and to top off the impending disaster, Rajon Rondo was suspended two games by the NBA after he threw the ball at referee Sean Wright in Sunday’s game.

In an utterly unsurprising result, they got blasted, 89-73. Give the Celtics who did play some credit. It could have been much worse.

WHAT WENT WRONG

– Without Garnett in the lineup, the Celtics had no one who could guard Dirk Nowitzki. Not surprisingly, the Mavericks took full advantage, not only running their offense through Nowitzki, but also getting Chris Wilcox into quick foul trouble, forcing the Celtics to use Mickael Pietrus on the All-Star.

– Rondo’s going to take some criticism for his suspension and all of it is justified. With his team falling apart, he simply can’t afford to let his emotions get away from him like they did on Sunday. It wasn’t the first time he’s whipped a ball at an official after a call he didn’t like and the NBA came down hard with a two-game suspension. Rondo is 25 years old. He’s a six-year pro and a two-time All-Star. This isn’t about growing up or maturity. It’s about keeping your composure when your team needs you and Rondo messed up. Simple as that.

– Just for kicks, Jermaine O’Neal sprained his wrist and didn’t return to the game. Ditto for Wilcox who strained an abductor muscle. At one point, the Celtics had Marquis Daniels and Pietrus at forward with Keyon Dooling and Ray Allen in the backcourt and Greg Stiemsma at center. That was one of the more conventional lineups the Celtics used in the second half.

WHAT WENT RIGHT

– Avery Bradley played 33 minutes and scored 12 points on 6-for-11 shooting with four rebounds, two assists and just one turnover. He played about as well as could be expected.

– Thanks to a late barrage of 3-pointers from the small-ball lineup, the Celtics were able to avoid a season-low in points. The Phoenix game lives on for another night.

For brief stretches of Sunday night’s game against the Pistons, the Celtics looked like a competent basketball team. For most of the night, however, they looked like a team that would rather be anywhere but on the court.

It was hard to pick one moment that stood out as the worst in their 96-81 loss. There was the disastrous second quarter that saw them turn the ball over nine times while allowing six offensive rebounds and 16 free throws. Then there was Rajon Rondo getting thrown out late in the third quarter after a half-hearted comeback attempt had already run out of steam.

The Pistons shot a staggering 46 free throws, compared to 15 for Boston. Say what you want about the officiating — and the Celtics said plenty, picking up four technical fouls — but that speaks volumes about who was the aggressive team.

The Celtics are a .500 basketball team again and with games against the red-hot Mavs and the West-leading Thunder coming up, there’s a decent chance they will be less than that when the All-Star break mercifully happens next weekend.

WHAT WENT WRONG

– The Celtics scored 26 points and shots 65 percent in the first quarter. They had assists on eight of their 11 made baskets and the scoring load was evenly distributed between Paul Pierce, Chris Wilcox and Jermaine O’Neal. That was when Rondo went out of the game for a break, and once again the Celtics’ second unit failed to do anything offensively. It took them almost a quarter to score a basket and by that time Detroit had run up a 38-29 lead. Things were about to get worse.

– The Celtics committed 18 fouls in the first half, yielding 29 free throws. This, naturally, led to complaints about the officiating from Doc Rivers and Wilcox, who were both given technical fouls. Both men had valid complaints, but the Celtics were fouling guard Rodney Stuckey almost every time he drove to the basket because they couldn’t stay in front of him and they weren’t going to the line themselves because they once again turned into a jump-shooting team.

– Of course, the officials had nothing to do with the fact that the Celtics turned it over 13 times and yielded 10 offensive rebounds in the first half.

– Frustrated over a lack of calls, Rondo got shown the gate when he whipped the ball at referee Sean Wright late in the third quarter. The Celtics need more from their point guard.

– JaJuan Johnson got pushed around physically by the Pistons front line. He better get used to it because that’s how it’s going to be every night until he proves himself.

WHAT WENT RIGHT

– The Celtics once again kept a team under 40 percent shooting. It would have helped if they had rebounded those misses.

– O’Neal had eight points, five blocks and 11 rebounds.

The Celtics were good, bad and then good again against the Bulls on Thursday. Unfortunately for them, the game was four quarters long and by the time the C’s had pulled even with Chicago, they were out of gas. Give them credit for hanging in there against a tough team on the road on the second night of a back-to-back, but the Celtics should be way past moral victories at this point of the season.

The offensive balance returned as Rajon Rondo, Ray Allen, Paul Pierce and Kevin Garnett all took between 12 and 17 shots apiece. Together, they took about 75 percent of the team’s shots. They just simply didn’t make enough. The defense also returned to previous level with the return of Garnett as they held Chicago to 40 percent shooting. But they gave up too many offensive rebounds (16) and fouled too much (the Bulls had a 28-18 edge in free throws).

It will go in the books as 89-80 loss, their fourth in the last five games and their long road trip is off to a frustrating start.

WHAT WENT WRONG

– Everything that happened in the second quarter. The Celtics were outscored 26-11, but that doesn’t even begin to scratch the surface. They shot 3-for-15 and were outrebounded 19-4. Omer Asik and Taj Gibson had seven offensive rebounds between them and played only four minutes each. They were scoreless for the first three and a half minutes of the quarter and didn’t make a basket until it was halfway over. Even all that doesn’t do justice to how poorly they played.

– Chris Wilcox and JaJuan Johnson have made their contributions by being energy players. For three quarters, their collective batteries were on low. Wilcox picked up his game in the fourth, thanks to some highlight-worthy lob passes from Rondo. The rest of the bench play was ineffective at best and disastrous at worst. Without an effective second unit to provide support, the Celtics’ starters ran out of steam.

– Speaking of Wilcox, his fourth quarter technical foul couldn’t have come at worse time. The Bulls pushed their lead from five to eight and he went to the bench in favor of Jermaine O’Neal. The momentum the Celtics had built was gone.

WHAT WENT RIGHT

– Not so surprisingly, it turns out that Rondo and Pierce can co-exist when both players are aggressive. Less than 24 hours after a dismal offensive performance against Detroit, Pierce started Thursday’s game looking to score. He made three of his first four shots and while Pierce was doing his thing, Rondo stayed in the background. Once Pierce cooled off, Rondo took over. Together, they took 15 of the team’s 25 shots in the first quarter and set the tone for the rest of the night.

– Ray Allen missed his first seven shots, but caught fire at just the right time, knocking down three straight 3-pointers as the Celtics pulled to within one point by the end of the third quarter after being down by double digits.

– Rondo operating in the post continues to be an intriguing wrinkle for the Celtics. While he’s not a true scoring threat on the block, getting Rondo isolated under the basket with shooters spaced out around him practically dares opponents to try and double-team him.

– Garnett had a double-double in his return from a hip flexor with 18 points and 10 rebounds. The Celtics desperately need him to stay healthy the rest of the season if they are going to have a chance.

JaJuan Johnson will have a chance to play for the Celtics. (AP)

Moments before JaJuan Johnson‘s breakout game as a member of the Celtics, his coach was asked if the skinny 6-foor-10 rookie was ready to take on a more meaningful role.

“Not yet,” Doc Rivers replied quickly. “I think he’s getting close. You’ve got to execute when you’re on the floor. That’s an area he has to improve on. He’s talented, but there’s a level, to me, of intensity that you have to play with every night and focus and he’s inconsistent in that. But he’s getting there and he’s a great kid and he will get there.

“We want to use him, but he has to come get it,” Rivers continued. “We’re not going to give him anything.”

Johnson went and got it on Sunday against the Bulls and their talented — and huge — frontline. After a rough first few minutes, Johnson scored 12 points on 6-for-13 shooting and managed to hold his own on the boards. He was credited with just one block, but it seemed like he altered several other shots. Even when the likes of Omer Asik and Joakim Noah were playing through the generously-listed 220-pounder, Johnson kept competing.

As is his custom, Rivers handed out praise judiciously to his young player.

“Yeah, but he’s got to keep doing it,” the coach said. “You know, one game doesn’t make a star. One season doesn’t make a star. So you’ve just got to keep doing it, and he’s got to do it consistently. He will, like I keep saying, he’s a great kid and he wants to do it. He’s young and he’s still learning focus and all that. But he’s a good player.”

Johnson is the latest young player on the Celtics’ roster to get his chance at making a meaningful contribution. With Brandon Bass sidelined for up to two weeks with swelling in his knee and Jermaine O’Neal missing the last two games with an assortment of injuries, Johnson is one of three healthy frontcourt players alongside Kevin Garnett. The others are Chris Wilcox and Greg Stiemsma.

Johnson has patiently waited his turn while fellow Purdue rookie E’Twaun Moore has already made an impact as a reserve guard, and second-year player Avery Bradley has grabbed hold of the backup point guard job. Even Stiemsma, the 26-year-old veteran rookie has been ahead of the first rounder, but Johnson’s talent has been on display, albeit in only 103 minutes with most of that coming in garbage time.

With a huge small-sample size warning blaring in neon blinking lights, Johnson is shooting 55 percent and averaging 18.2 points and almost six rebounds per 36 minutes. He made 3-of-7 shots from 16-23 feet and seems comfortable taking the jumper in the halfcourt. Johnson also got out on the break and finished at the rim, including a highlight-reel alley-oop lob from Rajon Rondo late in the fourth quarter.

Johnson’s breakout performance followed a forgettable seven-minute stint against the Raptors on Friday when he seemed hesitant and confused on the court. Rivers called two quick timeouts and let Johnson — and the rest of the team — have it. Still, without much practice time to work on his game, Johnson has drawn praise from Rivers for his mature approach.

As with the other young players, the hard part starts now. Johnson must perform consistently, night in and night out, while Bass and O’Neal are injured. One game does not a career make, but for the other rookie from Purdue, Sunday afternoon was a positive step.

Oddly enough, the Celtics have not been that bad in back-to-backs this season. Coming into Friday’s game against the Raptors, they had won four of six on the second night and each of the last three.

However, all four of those wins had been at the Garden and their two losses — at New Orleans and Indiana — ranked as two of the worst losses of the season. You can add Friday night’s 86-74 loss in Toronto to the list as the Celtics looked not only old and tired, but disorganized and ineffective.

They scored 14 points in the first quarter and 17 in the third, placing the blame squarely on the shoulders of the starting five.

WHAT WENT WRONG

– Rajon Rondo put together perhaps his most ineffective nine minutes as a Celtic, taking two shots, missing both and turning the ball over four times with no assists. He wasn’t much better in the second quarter, either. Or the third, or the fourth. In what was Rondo’s worst game of the season, he scored five points on 2-for-10 shooting, while allowing Jose Calderon to score 17 points and hand out 13 assists.

– It wasn’t just Rondo. Ray Allen and Paul Pierce combined to shoot 7-for-19. Rondo, Allen and Pierce were outscored by Calderon, DeMar DeRozan and James Johnson by a combined score of 52-23.

– Jermaine O’Neal joined Keyon Dooling and Sasha Pavlovic on the injured list. O’Neal has somewhat remarkably missed only five games this season and has already played 49 more regular season minutes than he did all of last season. Somehow, someway the Celtics have to get through the rest of the season with O’Neal playing 75 percent of the games.

– The Celtics switched to a zone to get more shooting on the floor, but they didn’t play it well. The Raptors made just 1-of-11 3-pointers through the first three quarters, but buried 4-of-8 in the fourth.

WHAT WENT RIGHT

– Avery Bradley, on the other hand, did what Avery Bradley does. He caused havoc on the defensive end, brought the ball up the court without incident on the offensive end and then got out of the way. Unfortunately, Bradley could only give them seven minutes because of an injured shoulder.

– Kevin Garnett scored 17 points and had eight rebounds, but it wasn’t nearly enough.

Rajon Rondo and Paul Pierce have made solid cases for inclusion on the All-Star team. (AP)

Through his first 11 games of the season, Paul Pierce averaged less than 15 points a game and shot 37 percent from the floor. He also averaged fewer than five rebounds and a little more than four assists.

The Celtics lost six of those 11 games, including the first-ever five-game losing streak in the new Big Three era, and when that was combined with an 0-3 start without Pierce while he was recovering from a bone bruise in his heel, there were naturally questions about whether it was all over for this group of Celtics.

Then Pierce scored 34 points against the Wizards to go with eight rebounds and 10 assists, and that kickstarted a remarkable renaissance. Over the next 10 games, Pierce averaged 22.6 points, 6.6 rebounds and 7.4 assists and the Celtics went 9-1 with Pierce leading the way.

Are those 10 games enough to make Pierce an All-Star?

Through the first 13 games of the Celtics season, Rajon Rondo essentially carried the offense. With Pierce injured and then working his way back into game condition and Kevin Garnett off to a slow start, the Celtics asked Rondo to take on more of an aggressive role and he attempted almost 200 shots (making 52 percent of them) while handing out 122 assists.

The Celtics weren’t good, but Rondo was, rebuilding his reputation after a late-season swoon in 2011 and an offseason of trade rumors. Then Rondo fell awkwardly on his right wrist and missed eight games. The Celtics went 6-2 and when he came back he was able to return to his preferred playmaking role, racking up 28 assists in his last two games.

Are 16 games enough to make the All-Star team?

After the starters are chosen by the fans, the reserves are selected by the coaches who vote for two guards, two forwards, a center and two wild-card choices. They will be announced before the Celtics play the Lakers on TNT on Thursday night. There are roughly 20 players in the East who could be considered for the honor, but only a few truly stand out. Compare that to the West where the competition is tighter, but also much tougher.

It says more about the Eastern Conference than it does the seasons that Pierce and Rondo are having that the answer is yes — although there is more of a debate in Rondo’s case.

With the obvious exception of LeBron James — who is the clear front-runner for MVP — Pierce has been the most productive small forward in the East. Among players at his position in the Eastern Conference, Pierce ranks second in true shooting and assist percentage behind LeBron and he grabs rebounds at roughly the same rate as Andre Iguodala and Luol Deng.

That’s including the first 11 games when even considering Pierce for an All-Star berth would have been laughable. His last 10 make his selection an obvious choice.

Rondo’s competition among point guards comes from the trio of Brandon Jennings, Deron Williams and rookie Kyrie Irving. In Rondo’s favor he has the highest True Shooting, assist percentage and rebound rate among the four guards. Working against him is the simple fact that he’s missed a third of the team’s games in this condensed schedule.

It should also be noted that picking an All-Star team after 24 games of a season like this essentially comes down to subjective arguments. Does Rondo get credit for picking up his game when his team needed him, or penalized for not winning more games? Without Williams, are the Nets the Bobcats? The argument here is that Rondo has been statistically the second-best point guard in the East after Derrick Rose, but the margin is thin.

Here are my selections for both the East and Western Conference All-Stars.

EAST

Starters: Derrick Rose, Dwyane Wade, LeBron James, Carmelo Anthony, Dwight Howard

Guards: Rajon Rondo, Joe Johnson

Forwards: Paul Pierce, Chris Bosh

Center: Tyson Chandler (narrowly over Anderson Varejao)

Wild cards: Andre Iguodala, Josh Smith

Toughest omissions: Deron Williams, Greg Monroe, Tyson Chandler, Kevin Garnett, somebody from the Pacers

WEST

Starters: Chris Paul, Kobe Bryant, Kevin Durant, Blake Griffin, Andrew Bynum

Guards: Russell Westbrook, Steve Nash

Forwards: Kevin Love, LaMarcus Aldridge

Center: Marc Gasol

Wild cards: Tony Parker, Paul Millsap

Toughest omission by far: James Harden

Other omissions: Kyle Lowry, Pau Gasol, Monta Ellis, somebody from the Nuggets