Bosh was scheduled for an MRI to determine the extent of the problem.
"He was in a little bit of pain going into the locker room," Heat coach Erik Spoelstra said. "We won't know until we get an MRI."
Ronny Turiaf started the second half in Bosh's place. Joel Anthony and Turiaf combined got 13 points and 10 rebounds on 6-for-8 shooting for the Heat, who took Game 1 of the series 95-86.
Bosh scored 13 points on 6-for-11 shooting in the first half, the last three of those points coming with 1:06 remaining after a dunk while getting fouled by Indiana's Roy Hibbert. Bosh remained down for a few moments, then got up slowly and made his free throw.
While going back down to the defensive end, Bosh started limping and grabbing at his midsection. He eventually fell to his knees in pain, and was replaced by Turiaf with 43.6 seconds left. Bosh was grimacing as he walked toward the Heat locker room for evaluation, and the team announced the diagnosis of his injury during intermission.
With Bosh out, LeBron James and Dwyane Wade combined to score 42 of Miami's 53 points in the second half, outscoring the Pacers by themselves. Indiana managed only 38 points in the second half.
"I knew I was first or second option," Wade said. "I was just trying to be more aggressive. They did a great job of getting me the ball. I was able to make the shots."
Bosh averaged 15 points per game on 51 per cent shooting in Miami's first-round win over the Knicks. He played in 57 of Miami's 66 regular-season games this season, missing three because of a death in his family and the last six games before the playoffs with a hamstring problem.