WALTHAM, Mass. -- Celtics rookie Jared Sullinger attributes much of his basketball development to his three older brothers: James and Julian Sullinger, and Kevin Garnett.

OK, so there's no blood relation between Jared Sullinger and Garnett, and the "Big Ticket" initially bristled Thursday at the suggestion of being the "Big Brother," but he ultimately acknowledged the supporting role he has played in nurturing Sullinger this season.

Spearheaded by blossoming play at both ends of the floor, Sullinger finds himself the team leader in plus/minus through 35 games, having surged past the "Big Plus/Minus" himself. Coming off a plus-24 effort in Wednesday's win over the Phoenix Suns -- one in which he registered 12 points and a career-high 16 rebounds -- Sullinger now is plus-66 for the season (Garnett, the perennial leader in that category, is second on the team at plus-44).

That tells only part of the story. Sullinger endeared himself immediately with a relentlessness on the glass, but his defense has improved, he's quietly finding ways to chip in offensively without needing plays designed specifically for him and he's simply making good things happen on the court (as evidenced by his glossy plus/minus stats).

"I can always hear him in the back of my head," Sullinger said of Garnett. "He's always trying to mentor me, tell me what I can do, what he sees. Trying to make me see what he sees." Yoon S. Byun/The Boston Globe/Getty Images

But a quiet toughness -- a venerable mean streak -- has emerged from a player who jokes that off the court he's as cuddly as a teddy bear. Heck, even Garnett noted, "He's a guy you want your daughter to bring home." Just don't put him on the basketball court with your daughter.

During Monday's slugfest with the Knicks, Sullinger earned some stripes with teammates. After producing a fourth-quarter block on Carmelo Anthony, Sullinger won a scramble for the ball only to find himself swarmed by Tyson Chandler. The two wrestled for the ball. Sullinger was unwilling to give it up to the hulking 7-foot Chandler and earned a whistle -- and a Chandler shove -- for his trouble.

Celtics coach Doc Rivers noted how Chandler -- infuriated by the rookie -- proceeded to bark at him on the Boston bench throughout the final frame. Back in teddy bear mode, Sullinger simply laughed at him. It's a careful balance between playing a physical game and not letting emotions overtake him.

That's a lesson he learned on the playground with his older brothers at age 6.

"A little story of mine: One day we went to the park, and it was me and my brothers. I went for a layup, and Julian just pushed me into the pole," Sullinger said. "I started bleeding, so I went running home. I'm crying to my mom, and my mom's like, 'Go see your father.' My father told me, 'Do you want a trophy saying that you're the best player ever, or do you want to go earn that trophy that says you're the best player ever?' And, you know me, I was like, 'Just give it to me.' He was like, 'No, go back out there.' So my mom cleaned me up. She patted me on the back and said, 'Good luck, baby.' And I went back out there, and we started playing again."

That's tough love. But it made Sullinger a tougher player between the lines.

Fast-forward to this summer. Sullinger, after watching his draft stock plummet due to red flags about his back, slid to the Celtics at No. 21 in June's draft. Sullinger would deem it a blessing, in part, because of the ability to learn under Garnett's tutelage.

The first time on the floor together during informal workouts, the 36-year-old Garnett welcomed the 20-year-old Sullinger to the league in big-brother fashion.