As Austin Powers reminded us, the idiom of a steamroller as an overwhelming, irresistible force isn’t exactly an apt one. Rather, the plodding machine goes about its business, transforming a bumpy road into a smooth, consistent surface. And so goes the NBA life of Greg “The Stiemroller” Stiemsma.

Since amassing 13 points and seven rebounds during his first career start just six games into his rookie season, Stiemsma became somewhat of a cult hero in Boston — Brian Scalabrine 2.0, if you will — particularly after Tommy Heinsohn compared his shot-blocking prowess to the legendary Bill Russell.

Except, the “Scal-a-bri-ne” chants that so often enveloped the Garden came in the final moments of blowout victories by a championship-contending team, a Gino-esque symbol that signaled another opponent throwing in the proverbial white flag. The opposite is true for this group of Celtics, whose lack of depth in the frontcourt requires a nightly contribution from the 7-foot Stiemsma if they hope to accomplish anything in the playoffs.

“I don’t think there’s been one real moment that it kind of all clicked in, but this whole season has been about opportunities,” said Stiemsma. “Early on, even in the preseason and the training camp, I had certain opportunities, and I got to play well in those opportunities. So, I think early on it helped me establish just in my own head that, ‘All right, I can play at this level and proved that.’

“So, even if I have a bad game or have a bad possession, whatever it is, I can just get over it and not worry about the big picture of ‘Maybe I’m not cut out for this level,’” he added. “I think I’ve proved that I am.”

Doc Rivers is forced to play Greg Stiemsma, and it's paying dividends for the Celtics. (AP)

The road hasn’t always been so smooth for Stiemsma. He went from leading Randolph (Wis.) High to three straight state titles, to averaging just 2.7 points and 2.3 rebounds in 85 games over four years while battling depression at the University of Wisconsin, to the 2011 Pan American Games in Mexico as a member of the bronze medal-winning USA Basketball squad, and to Turkey (twice), South Korea and Sioux Falls (twice).

“The journey I’ve been on, I’ve had a lot of losses, and that’s something I haven’t really experienced in my career at any level,” he said. “Growing up as kids, we expected to win every game. Then overseas, to be on a below .500 team, that was tough. So, it feels good to be here in a winning program. There’s a lot of expectations, too. We step on the floor and expect to win every night. We have big plans for the rest of the year.”

Even this season has had its share of ups and downs. Between his breakout performance back on Jan. 2 and March 6 — the night before Chris Wilcox played his final game of the season — Stiemsma didn’t score more than four points over a 30-game span that included seven DNPs. Not to mention a laundry list of injuries to his right foot (bone bruise), left foot (plantar fasciitis), right thumb (jammed) and right pinkie (“just a flesh wound”).

“There’s always little bumps and bruises that you get throughout the season,” he said. “This year, with the situation we’re in, now that Ryan [Hollins] is here we have a little bit of help, but otherwise we didn’t really have a choice. I’ve worked too hard to get to this point to let a couple little injuries keep me off the floor. It’s been a journey to get here, so I’m not going to let something little keep me off the floor.”

Without Wilcox and Jermaine O’Neal for the remainder of the season, the Celtics will rely heavily on Stiemsma to ease the load at center placed on Kevin Garnett‘s shoulders, at least until Hollins can pick up the system.

“Greg’s been huge since the departure of J.O. and our lack of big men,” said Garnett. “I think he’s stepped in and been solid for the road that we need him. He understands what we’re doing here, he understands his role, and I think he plays his role very well.”

In his last 12 games, Stiemsma is averaging 4.3 points, 3.7 rebounds, 2.3 blocks and 1.1 steals in 18.4 minutes a night. Count Scalabrine among those who never had a month that productive in a Celtics uniform. For the season, the former NBA Development League Defensive Player of the Year has produced 7.2 points, 8.6 rebounds, a rookie-best 4.2 blocks, 1.6 steals and 1.4 assists per 36 minutes. In other words, opportunity taken.

“I think my confidence is coming,” said Stiemsma, who totaled 10 points and seven boards in Sunday’s win over the Wizards. “It’s been building all season, and right now I feel about as good about my game as I have all year.”

That confidence was on display Sunday, when Stiemsma took four shots from 10-23 feet, knocking down three of them — both forcing opposing defenses to respect him and opening up things for his teammates. “I mean, I’m sitting there wide open from 15 feet,” he said. “I’ve gotta knock those down.”

Asked what he’s noticed from Stiemsma in recent weeks, Celtics point guard Rajon Rondo added, “Just his confidence shooting the ball. He’s knocking down the elbow 15-footer shot, getting a lot of blocks out there and his defensive rotations are getting better.” To be sure, that last note goes a long way in Doc Rivers‘ eyes.

Sunday’s line was a similar one to his first career start almost three months ago, only now it’s no longer a surprise but an expectation from Stiemsma. His last last seven games have also included an eight-point, eight-rebound effort in a two-point win over the Warriors and a hodgepodge of six points, five blocks, four rebounds, four steals and three assists in a 100-91 victory against the Bucks in his return to Wisconsin.

Coincidentally, while Stiemsma performed well in his home state, his Badgers were back in Boston, losing a dramatic 64-63 Sweet 16 matchup against Syracuse. Still, Wisconsin head coach Bo Ryan found the time to leave some encouraging words behind for a player he may regret underutilizing.

“That Badger smell is still kind of hanging in the locker room,” said Stiemsma, later adding, “There’s a little note in my locker. It just says, ‘Coach Ryan was here. Best of luck.’”

Stiemsma’s journey from worldwide basketball journeyman to entrenched backup NBA center has been anything but lucky. He’s earned each opportunity, his confidence growing every step of the way — perhaps never more evident than when on multiple occasions Stiemsma gave referee Michael Smith the stink eye after a whistle.

“Some of these rookie calls, hopefully they’re going to start fading a little bit. It is what it is,” said Stiemsma, laughing. He added, “That’s part of the game, interaction with the officials. You’ve got to feel them out a little bit. You’re obviously not going to change their mind. I’ve yet to do that, to see them reverse a call.”

Just one more obstacle for the Stiemroller to iron out on his road to NBA legitimacy.

(Have a question, concern or conception for tomorrow’s Irish Coffee? Send a message to @brohrbach on Twitter.)