"Portland -- there's an outside chance that could be the return game," Rivers said before Thursday night's game against Chicago at TD Garden. "Outside chance. There's a chance."
With the Celtics off the day before the Portland game, Rivers said Garnett could potentially have a day of practice before returning to game action.
But Rivers stressed that the team would not rush Garnett back.
"We'll play him when he's ready," said Rivers.
Garnett has been sidelined by a hyperextended right knee after being kicked in his surgically repaired knee against Golden State on Dec. 28. He started working out on Monday after a period of inactivity to allow the hyperextension to heal.
The banged-up Celtics should get some help before Garnett's return though. Forward Rasheed Wallace, who missed his third straight game Thursday with an injured left forefoot, is aiming to play in Boston's next game, on Monday when the Mavericks visit Boston.
Guard Marquis Daniels, who underwent thumb surgery last month, said after meeting with trainer Ed Lacerte Thursday, that he could have his cast off within "a week or two."
"I'll get it off in a week or two, maybe run and shoot a little bit, but no passes from [Rajon] Rondo," joked Daniels, who aggravated the injury on a bullet pass from Rondo during a December practice. He was examined by team doctors soon after and a torn ligament in his left thumb was discovered.
Daniels said he remains on pace for a post-All-Star Game return, but noted that it will take him some time to get back into the flow of things.
"I've been doing a lot of running, but that means nothing once you get out there and get ready to play in actual games," said Daniels.
Chris Forsberg is a roving reporter for ESPNBoston.com. Follow him on Twitter.