At the same time he doesn't want his aging stars out of game shape entering the playoffs.
An easy night against the Orlando Magic allowed him to satisfy both concerns.
The win locked up the seventh seed in the Eastern Conference for Boston, which never trailed in beating Orlando for the eighth straight time.
"It's a fine line between rest and health," Pierce said. "With this team you want to be as healthy as we can get at this point. Right now we're as healthy as we're gonna be for the rest of the season. ... If we play the next couple of games or if we didn't, the most important thing is that we're ready for the playoffs."
Tobias Harris led the Magic with 22 points, and Nik Vucevic added 16 points and 12 rebounds.
Orlando hasn't won back-to-back games since December. The Magic play their final home game of season on Monday against Chicago, and head to Miami for the season finale on Wednesday.
With the rest afforded to the veterans and extra playing time to the younger players, Celtics coach Doc Rivers feels good about his team in spite of the surprises dealt to it this season. He said he feels like the players are setting themselves up for a "pretty good run."
"I like our team. I like our team a lot," Rivers said. "The key for us is to get through these two games, have some great practices and get ready for the playoffs. That's what you play the whole season for."
The Celtics conclude their regular-season schedule against Indiana on Tuesday and at Toronto on Wednesday.
After resting their sore ankles the previous night, Celtics coach Doc Rivers re-inserted Pierce and Garnett into the starting lineup against the Magic.
They made an immediate impact, combining for 20 first-half points as the Celtics built a 20-point halftime advantage.
Garnett missed only one of his eight shots on the night.
"I'd like to see more consistency from us defensively," he said. "Obviously the roster will shrink a bit, that will alleviate a lot of other things. I've always loved our team ... as long as we play the right way."
The Celtics were able to add to their cushion in the second half against the young Magic, who are showing more signs of a team ambling toward the conclusion of an injury-plagued transition season.
With the exception of Harris and Vucevic, the Magic were mostly passive offensively and were a step behind on defence most of the night as Boston was able to work the ball around for easy looks.
"We have to get better," Magic forward Kyle O'Quinn said. "We have to take advantage of those teaching points. Those guys out there playing, we just have to learn everything we can from them."
The only brief moment of peril for Boston came late in the third quarter when Green remained on the floor after planting awkwardly on his left leg.
He stayed down a few minutes during a timeout, but was able to remain in the game. He said he was fine after the game.
A first-round matchup with the New York Knicks seems likely at this point for Boston, but it's not a mathematical certainty yet. Indiana still has a chance to slip into the second seed.
But whoever the opponent is, Pierce said it's clear the Celtics will need Green to be upright if they're going to be able to stick around in the post-season past opening round.
"Definitely, we're going to need him to step up," Pierce said. "He's going to be huge for us as that third scorer. And he has to be a third consistent scorer. Everybody already knows what me and Kevin bring. He's going to have to be that guy now.
"He's had some big games and he's gaining confidence by the game. And I think he's beginning to understand how important it is for him to continue being aggressive regardless of what me and Kevin are doing."
NOTES: Boston G Jason Terry was given the night off by Rivers, marking his first missed game of the season. He also will likely sit on Tuesday, Rivers said. ... The Magic used their 29th different starting lineup of the season on Saturday.