He retreated to the locker room at one point in the second half to redress the affected area but returned to the bench.
Sullinger said he started experiencing discomfort after Saturday's loss in Cleveland and that it was accompanied soon after by an illness. After conferring with the team's medical staff, Sullinger sought treatment at a local hospital and stayed overnight Monday before being discharged on Tuesday afternoon.
Sullinger called the past few days "rough" but added, "We've got some great doctors here, a great medical staff. And they did a great job to get me back healthy."
Doctors at the hospital advised Sullinger to consider sitting out Wednesday's game, and he was initially listed as questionable. After observing the team's pregame walkthrough, Sullinger elected to try to play through any discomfort.
"That was the whole point of going to the hospital, so I could play," Sullinger said. "One of the doctors told me, in a polite way, 'Maybe you should take a day off, try [returning on] Friday.' I said, 'Uh, you're not paying the bills at my house. I got to play Wednesday.'"
Sullinger said he felt slow on the court and didn't think his reaction time was back to normal.
Still, Celtics coach Brad Stevens raved about Sullinger's efforts on the glass during Boston's second-half surge, and Sullinger had a sequence early in the game in which he went coast-to-coast after a steal before scoring on a finger-roll and crashing after the bucket.
"I didn't think I was going to get that," Sullinger said. "That's when I realized how fatigued I was."
Asked if the infection was contagious, Sullinger said, "Not that I know of. If I am, that would be a great reason for [media members] not to talk to me."
When a reporter joked that some of the Grizzlies might have been less than eager to guard him because of the infection, Sullinger said, "They sure didn't act like it guarding me today."
Stevens applauded Sullinger's effort despite the lack of practice time.
"I thought he started the game, the first couple times he touched the ball he looked -- he did probably look like he was a little rusty from not having done much the last three days, but then he got himself going pretty quickly," Stevens said. "And I just think you know when we're going on that run, in any given game, it sure feels like he's getting almost every rebound, and that's what happened at the start of the third quarter."