He entered the game about four minutes into the third quarter, missed both his shots and didn't return as part of a gradual effort to improve his stamina.
"Just a little late on things, but (I) felt good overall," said Sullinger, the team's leading scorer and rebounder.
Coach Brad Stevens stressed before the game that it's unlikely Sullinger will play more than a couple of short stints during Boston's back-to-back games the next two days. The team has three days off after that, when it can evaluate his status.
"I don't know how much he'll be able to play, nor do I have many plans on playing him, to be honest," Stevens said before the game. "He'll be available if we need him. That was our discussion [Thursday]. He hasn't played or practiced with these guys. He is physically great, he has worked hard in all the things that he's needed to do and been able to do. But it's not the same as playing. And it's not the same as running up and down the court and playing. The way we're looking at it, he's available if needed this weekend, then we'll evaluate after that."
Asked before the game about what his role might be the rest of the season, Sullinger smiled and offered: "Good question. To be determined. I might play, I might not. Whatever it takes to help the team win. If it means waving my towel for those 48 minutes, then so be it."
Sullinger said he dropped 20 pounds over the past six weeks and credited the team's strength and conditioning staff with helping him start what he hopes is a transformation process after tipping the scales at 300 pounds earlier in the season.
When a reporter playfully asked if he was hiding a six-pack under his warmup shirt, Sullinger said, "Not yet. But made a lot of changes; made the right changes."
In late February, the team declared Sullinger would miss the remainder of the season with a metatarsal stress fracture in his left foot. Now, the Celtics plan to ease him back in while making a run at a final playoff spot in the Eastern Conference.
Stevens said he didn't know until recently that Sullinger would be available to play.
"I just assumed he was done for the year," Stevens said. "I knew that he was getting better; the reports that I was getting was that he was getting better. But he was cleared. I think that [team physician Dr. Brian McKeon] even came back [Thursday] and said, 'His foot looks absolutely fantastic.' He didn't have any hesitation on clearing him. He feels good about it. He's not at any additional risk or anything like that. It's not a rash decision, he's healthy. If he's healthy, he should be available to play."
Celtics president of basketball operations Danny Ainge said in a statement: "We are excited that Jared's recovery progressed quicker than initially expected. Jared was extremely diligent in his rehab, repeatedly expressing his eagerness to help our team reach the postseason. He will be available in a limited role this weekend as he works his way back to 100 percent game shape."
Sullinger's rookie season ended after 45 games in 2012-13 due to a back injury, and he appeared in 74 games last season. He was averaging 14.4 points and 8.1 rebounds in 28.7 minutes per game this season before the injury.
Stevens said Boston's push for a final spot in the Eastern Conference playoffs had no impact on the team's decision to bring the third-year big man back. But once the injury had healed sufficiently, there was little reason to keep him sidelined for the final seven games of the regular season.
The Associated Press contributed to this report.