The Celtics forward scored 19 points in 31 minutes, adding eight rebounds and a key steal with 16 seconds left to help Boston beat the Magic 109-106.
"These last two weeks have been dark days for me. Being hurt is not one of my favorite things," Garnett said after the game. "I've been doing a lot of things to get back here and get strong, and I was glad I was able to come out here and help my team out."
It was positive injury news all around for the Celtics, who also had Shaquille O'Neal (right adductor strain) and Semih Erden (groin pull) active in their frontcourt. O'Neal slipped on some ice on his way to the team's practice facility and sat out Sunday's practice, while Erden has been limited recently by a groin pull. Reserve swingman Marquis Daniels, who suffered what Rivers termed a "back stinger" running into a hard pick from Kendrick Perkins during Sunday's practice, was also available off the Boston bench.
But the pregame buzz centered on Garnett's return. Rivers said before the game that he wouldn't limit his minutes coming off the absence.
"We were only going to bring him back if he was right," said Rivers. "He's pretty much free to play now."
O'Neal's minutes, on the other hand, were be under the microscope.
"There's always a minute limit on Shaq and he went over it the other night," Rivers said after O'Neal logged a whopping 35 minutes, his biggest output since April of 2009 with Phoenix. "But again, we'll just see how it goes."
Rivers suggested Garnett could have returned Friday night against Charlotte, but some extra days of rest, as well as a full practice Sunday, only gave both player and team the assurance that he's ready to get back on the floor.
Garnett's return allowed forward/center Glen Davis, the team's sixth man, to slide back into a reserve role, bolstering a bench that's been up-and-down this season due to all the injuries.
Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter.