Pierce sat out Friday's 97-91 loss to lowly Cleveland with a sore left ankle, but returned to practice Saturday and should play against Washington (29-47).
Garnett's injury is more serious as he has missed the last eight games with inflammation in his left ankle.
"I have some issues with my foot and more from like the motion of the foot, just pressing it and pushing it like a gas pedal," he said. "It's an issue. If it isn't, I wouldn't be out."
The 15-time All-Star also practiced Saturday but it's unclear if he will play. Coach Doc Rivers certainly knows what he would like to see Sunday.
"He's been out a while and the playoffs are soon so the sooner he gets back out on the floor, the better and I would lean to him now that once he's cleared health-wise, it's probably better for him even if he can't play a lot of minutes to play in games because no matter what we do in practice, practice will never duplicate a game," Rivers said.
Boston (39-37) is trying to maintain its hold on seventh place in the Eastern Conference in order to avoid a first-round matchup with Miami. The Celtics lead eighth-place Milwaukee by two games.
"Obviously we're playing for something and obviously we're trying to get things done as we're out here playing so that's pretty much what it is," Garnett said.
Boston has dropped eight of 11, going 3-5 without Garnett in that span.
The Celtics have taken every meeting with the Wizards over the past two seasons, winning twice this past November by a total of nine points.
Washington did not have John Wall back then and Boston had a healthy Rajon Rondo. Now the advantage at point guard figures to swing to the Wizards since they have improved significantly since the electric Wall has returned.
The third-year guard posted his second-highest scoring effort of the season with 37 points Saturday in Washington's ninth straight home victory, 104-85 over Indiana.
"I think whenever you're feeling good and you're playing good, you're more into the game," said Wall, who missed the first 33 games recovering from a knee injury. "You're more enthused, you're more happy. ... After all the stuff I've been through this season with injuries and missing so many games, and having people say what they say about me, it means a lot."
The Wizards have dropped their last four on the road, and five straight at Boston. Wall is shooting 39.9 percent on the road compared to 49.4 percent at home.
Washington is 6-13 in the second half of back-to-back games.