By Brian Robb, CBS Boston

BOSTON (CBS) – Jared Sullinger came into the 2015-16 season with arguably more to prove than anyone else on the Celtic roster. Danny Ainge called out the fourth-year forward last February for his conditioning and weight issues that contributed to another slow start to the season by the Cs in 2014-15.

Largely without him, the Celtics soared to a 24-12 record over the final 36 games last year, leaving many to wonder if he would be a part of the team’s future, especially after veteran big men (David Lee, Amir Johnson) were brought into the fold this summer.

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With his back against the wall, Sullinger has pushed back with authority during his contract year. He worked his way back into the starting lineup and has outlasted the competition to become recognized as the most consistent Celtics big man for the first 61 games of this year’s campaign.

Where has the 6-foot-9 forward made the biggest impact over that stretch? Look no further than his work on the boards. Despite playing a meager 23 minutes per game, Sullinger is averaging a career-high 8.7 rebounds while anchoring the paint for Boston.

Those numbers don’t just make Sullinger the best rebounder for the Celtics. Compared to the rest of the league, Sullinger rates among the league’s best, particularly on the defensive glass. He has grabbed 28.2 percent of all available defensive rebounds when he’s been on the floor, the 7th highest mark in the NBA.

“To me, Jared is one of the best rebounders in the NBA,” Avery Bradley said after Sullinger posted 15 points and 11 rebounds against the Blazers Wednesday. “Whenever he has that mindset, it gets him going.”

While Sullinger’s rebounding has remained steady, he’s stepped up his contributions in other parts of his game in a major way since the All-Star break. He’s posted double-doubles in five of his eight games, averaging 12.3 points and 10.1 rebounds over that stretch, while shooting 48.1 percent from the field.

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“He’s done what he’s been doing the last, I mean, basically the whole season,” Isaiah Thomas said. “He’s been rebounding the ball, hitting open shots and playing great. And we need him to do that. When he plays at that level, it’s tough for us to be beat.”

“There’s a lot of good things that he brings to the table for us,” Brad Stevens added. “Hopefully he continues to play at a good level. He’s got to figure out in each game what his option is. There are times where he’s able to post and be really good down there. And then there’s guys that he can stretch because of his size and everything else.”

The sustained contributions and the Celtics’ success has opened the door for the 23-year-old to return to Boston next season. The big man will be a restricted free agent this summer, giving Ainge the right to match any offer he’s given by opposing teams. If it’s up to Sullinger he won’t be changing uniforms anytime soon.

“When you play for the greatest franchise in the NBA,” Sullinger explained, “And you see all those banners and all the fans, you don’t want to leave that place, because it’s a special place in your heart. It’s the first team I’ve played for in the NBA — hopefully it’ll be my last.”

If he keeps up his recent play, his chances of getting at least a few more years in Beantown are on the rise.

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Brian Robb covers the Celtics for CBS Boston and contributes to NBA.com, among other media outlets. You can follow him on Twitter @CelticsHub.