Perkins did not start. After starter Semih Erden picked up two fouls in four minutes, Perkins returned to the Garden floor with 8:02 to play in the first quarter. The Celtics faithful showered him with a prolonged standing ovation and he motioned to the crowd as he lined up on the baseline.
Less than a minute later, Perkins took an inside feed from Ray Allen and completed a layup while getting fouled. He missed the free throw.
Perkins, wearing a black brace over his right knee and showing some rust, checked out with 2:37 to play in the quarter, logging a little more than five minutes in his first shift of the night. He ended the night with seven points and six rebounds in 17 minutes as the Celtics beat the Cavs 112-95.
"It felt good," Perkins said. "The first quarter I got a little tired. After that I got my second wind and I was all right. It felt good to be on the floor."
"I thought he was terrific," coach Doc Rivers said. "I thought as the game went on his timing got better. I thought defensively he was terrific from the start. Just communication, we were loud again, defensively, which was nice. You could hear him and Kevin [Garnett] barking orders defensively and that makes us really good."
Perkins admitted he would have liked to have played more.
"When [Rivers] came and got me in the fourth [quarter], I really wanted to stay out there just to keep working on my rhythm and good things and just getting game time," Perkins said. "It was just cool to be out there, so it's all right.
Rivers said after Monday's practice that Perkins had asked to return for Tuesday's game, but Rivers dismissed the idea because he thought there was no way Perkins could return that soon.
But when team trainer Eddie Lacerte and team physician Brian McKeon walked into Rivers' office after the session, Rivers said he knew he was about to get some good news.
"The doctors walked in said they thought he should play," said Rivers. "I don't mind changing my mind."
Perkins, who tore the ACL in his right knee during Game 6 of the NBA Finals, had been projected after his surgery in July to return as late as the All-Star break, but recently pegged a Feb. 4 date against the Dallas Mavericks.
That timetable got accelerated and, while Rivers said he isn't expecting much from Perkins right away, he knows Perkins' return will give the team, which is battling injuries, a boost.
"It's great," Rivers said before the game. "I don't know how much he'll help us yet. He will, just his presence on the floor, but we're not activating him just because of that. We're activating him more because they say he's ready to play and the more days he plays, the better he'll be by the time it's the playoffs. That's just it."
Perkins' presence will help bolster Boston's frontcourt. Offseason acquisitions Shaquille O'Neal (hip) and Jermaine O'Neal (knee) are sidelined, leaving Erden in a spot-starting role that allowed Rivers to bring Glen Davis off the bench at both frontcourt positions.
Perkins' return gives the Celtics a psychological lift as well.
"He is always the guy that has been the hard-hat, lunch-bucket worker on the team," Allen said. "Just always has a great, hard-working mentality when he is out there on the floor.
"I think it has been well chronicled when he went down; obviously the eyes around the world were on him. Everybody felt a little bit of sympathy for us because we weren't whole. Him coming back has a great symbolism to it. We know what we are trying to get back to. We are trying to get this team back to where we are 100 percent."
Perkins resumed on-court, non-contact activity in late December, then said in early January that he hoped to be back on the court within three weeks. That optimism was tempered when his return to full-contact, full-team work was delayed initially.
Perkins returned to full activity on Jan. 16, reuniting Boston's starting five for the first time since Game 6 of the Finals.
Chris Forsberg covers the Celtics for ESPNBoston.com.