Pierce wore a white sleeve over his knee as he played pickup with Sam Cassell at the end of Sunday morning's shootaround at the team's practice facility. Rivers said Pierce showed no ill-effects of the right knee sprain that sent him to the locker room in a wheelchair during Game 1.
Pierce does not talk to the media after game-day shootarounds, Celtics spokesman Jeff Twiss said.
The news on center Kendrick Perkins, who sprained his ankle in Boston's 98-88 victory in Game 1, isn't as certain. He did nothing more strenuous than shoot free throws at the shootaround and will be a game-time decision for Game 2.
"There's just no reason to push him," Rivers said. "With an ankle, it's going to swell up. Let him swell up after the game instead of now."
If Perkins can't play, P.J. Brown would take his place in the starting lineup.
Both players responded well to the extra day of rest between the first two games of the best-of-seven series, Rivers said.
"I like the every other day rotation," Rivers said. "But in this case, we needed the extra day."
You can watch game 2 of the NBA finals on ABC30. Coverage begins at 6pm Sunday.
