WALTHAM — On Wednesday night, Celtics  coach Doc Rivers  looked out on the floor and saw Keyon Dooling , Avery Bradley , Mickael Pietrus  and Brandon Bass  and thought, this is what he’s been looking for. Energy, fullcourt defense, tempo, pace … all those buzzwords were finally on display.
“Without the second unit [Wednesday] night we’re losing that game by 25 points,” Rivers said. “The second unit got us back in the game with their energy defensively. That’s how I envisioned them when we started this and that was the first night where you could literally see the difference, and probably because Pietrus was part of it.”
Rivers said after the Celtics’ 90-85 loss to Dallas that his new swingman brought a “joy” to the court in his debut. An upbeat, gregarious character, Pietrus quickly endeared himself to his coach, his teammates and the Garden crowd with 18 inspired minutes.
He was playing so well that Rivers left him in the game deep into the fourth quarter before bringing back Paul Pierce  at about the 6-minute mark, who had his second straight poor game. Pierce has not talked with reporters since Tuesday when he held court for several minutes after practice, but Rivers said Pierce was fine with the decision.
The second unit didn’t overwhelm anyone with their statistics. They scored 27 points, 19 of them from Bass and Dooling, and had 10 rebounds and four assists. They began coming into the game down 17-9 after the starters got off to a woeful start offensively and by the time they had rotated back out halfway through the second quarter they had cut two points off the lead. Again, not overwhelming, but successful.
Rivers has pinned his team’s 4-5 record on the starters. What he wants from his bench are energy, defense and the ability to shake things up when things start poorly. He’s still searching for the right combination of players, which is understandable.
The Celtics acquired nine players via trade, draft and free agency and all of them come off the bench. Bradley played only 162 minutes last season, so he is also new to the rotation. That’s a lot of moving parts and Rivers has already worked through several variations of a reserve unit.
Here’s how they stand at the moment:
Keyon Dooling: Rivers has decided that Dooling is not a point guard and the numbers back that up. He has 18 turnovers and only 11 assists. The turnovers are out of character for Dooling, but he’s averaged 4.1 assists per 36 minutes for his career. What he can do is shoot and provide some semblance of instant offense, like his nine points in 13 minutes against Dallas. “Keyon’s better at the two spot than he is at the one,” Rivers said.
Dooling sat out practice with a sore knee and he’s questionable for Friday’s game with the Bulls. If he can’t play it will be interesting to see which way Rivers goes. In the last few days, the coach has mentioned the need for Bradley or rookie E’Twaun Moore  to take on more ballhandling responsibilities.
Avery Bradley: Yes, the second-year guard hoisted one of the ugliest bricks you’ll ever see on a wide-open 3-point attempt, but he also scored four points on drives to the basket, collected three rebounds and had two assists against one turnover in 11 minutes. His offense remains raw, but Bradley is starting to get it and Rivers loves to have him hound opposing ballhandlers fullcourt.
Mickael Pietrus: It took one game, and maybe less, for Pietrus to jump Marquis Daniels  in the rotation. Daniels has been off to a dreadful start, shooting just 27 percent and Rivers left no doubt how that situation stands.
“Either they’ll play together or Pietrus will play because Pietrus is playing, I can tell you that,” Rivers said. “Then Marquis will fit in whenever we need him.”
Brandon Bass: Easily the best addition, Bass has come back down to earth since his scorching start but he’s giving them 12 points and 6 rebounds in 28 minutes a night. The issue for Bass and the Celtics is that when he plays with Kevin Garnett , they become very small up front.
That played out late in Wednesday’s game when Dirk Nowitzki  beat Garnett off the dribble and then scored by going right through Bass who tried to contest him at the rim. After the game Rivers, second-guessed himself for not putting Jermaine O’Neal  back in the game to protect the rim.
Greg Stiemsma /Chris Wilcox : Stiemsma played three minutes in the first half and Wilcox played three in the second half, so this isn’t a huge role, but the Celtics need more here, particularly from Wilcox who has scored just seven points in 48 minutes.
“I think it will go on the type of game it is.,” Rivers said. “If it’s a physical energy game I think those are the Wilcox games. If it’s a length game, then it’s a Greg game. Neither one of them have separated themselves.”
While it would be a mistake to think he’s been written off entirely, Daniels has played himself out of a role as has Sasha Pavlovic  who was uninspiring as a fill-in starter for Pierce and hasn’t played a meaningful minute since Dec. 30 against the Pistons. The Purdue rookies remain in a holding pattern. Moore remains ahead of JaJuan Johnson  in terms of opportunity but neither player has earned time yet.