The Celtics coach knew all about Sullinger’s game, even saw the 240-pound teenager haul in 27 rebounds once for his All-Ohio Red AAU team. Rivers’s son, Austin , played for Each 1 Teach 1, which Doc said lost to the Ohio Red in at least six national title games.

WALTHAM — Doc Rivers used to refer to the 16-year-old Jared Sullinger as the “fat, slow guy.”

Rookie Jared Sullinger, who was hit in the right eye late in Wednesday’s win, got his longest look yet in the NBA.

What Rivers didn’t know is the same thing everyone else in the NBA seems to be discovering after letting Sullinger fall to the Celtics with the 21st overall pick in last year’s draft.

“Now I realize: He’s not slow, he’s actually not fat — he’s just round,” Rivers said. “But he has great feet. He really does.”


The 6-foot-9-inch, 260-pound rookie set a season high with 16 rebounds Wednesday, playing 34 minutes (another season high) in an 87-79 win over the Suns — despite playing against 6-11 Marcin Gortat.

Sullinger, 20, is ranked 15th in the NBA in total rebound percentage, which measures the available rebounds a player grabs. According to basketball-reference.com, Sullinger has hauled in 18 percent of his available boards, which is less than 1 percent fewer than Dwight Howard and DeMarcus Cousins.

Against a Suns team that scored 50 of its 79 points in the paint, Rivers needed to go big, and Sullinger played big.

“He’s very poised,” said Kevin Garnett. “You’re not going to get under his skin. And practice every day is not easy. Our practices are hard. They get emotional, passionate.

“The games — there’s popcorn popping and concession stands, and [the media] sitting three seats away from us. The practices are real and they get intense at times.”

Sullinger showed signs of growth all throughout Wednesday’s game, but two moments stood out.

First, when he realized that Jared Dudley had been lost in coverage and was standing alone on the 3-point line, Sullinger left his inside position and darted over to Dudley, just in time to get a hand in his face and distract the shooter. Dudley launched an air ball at a time when the Suns were trying to crawl back into the game.


And second, late in the game, Sullinger came up with a clutch rebound, much to the dismay of Luis Scola. Scola, who apparently had had enough of getting outshined by a rookie, started to get physical, wrapping his body around the young Celtic. Sullinger came up swinging his elbows to protect himself, enticing Scola into committing a foul.

Sullinger, said Garnett, “is a nice guy, but you don’t bring that nice guy onto the floor. And he understands that.”

Second wind

After posting season lows in points (7) and minutes (24), Paul Pierce said Rivers was ready to put him back into the game during the second quarter Wednesday but the 15-year veteran declined.

“We made the run and I was like, ‘No, let the second-unit guys continue to play,’ ” Pierce said. “They were playing well at the time and making a run.

“It’s always a plus when I don’t have the pressure of scoring so many points and playing so many minutes. It’s a long season.”

Ref roadblock

Rivers was whistled for a technical Wednesday, shortly after Jason Collins thought he took a charge that was never called. The coach said he’s been trying to get his team to take more charges, and explained why Thursday.


“It’s just a great play,” Rivers said. “I do get upset when a guy takes them and [officials] don’t give them. It’s almost like there’s a rule sometimes that if you take two or three, ‘Well, we can’t give you five charges in a game.’ We say, ‘Why not, if we take five charges?’ ”

Wilcox on track

Chris Wilcox, who hasn’t played since Dec. 18 because of a sprained ulnar collateral ligament in his right thumb, returned to practice Thursday. Wilcox was originally expected to miss about a month. Although Rivers said he was ahead of schedule, the coach wasn’t sure when the forward would return to game action . . . Fab Melo was on the practice court as well, but team officials said he had not been cleared for contact following a concussion suffered from hitting his head on a door during his time with the Maine Red Claws of the D-League. Melo is expected to return to the D-League when healthy.