The top reserves did not take part in Miami's shootaround Wednesday and were game-time decisions.
Andersen, who bruised his thigh in a collision with teammate Dwyane Wade in the Heat's Game 3 win Saturday, sat out Monday's 102-90 victory as Miami took a 3-1 series lead. Allen bruised his hip and thigh as he attempted to run through a screen in the second half of Monday's win.
Both Andersen and Allen finished the games despite their injuries.
Andersen has been getting constant treatment for the past three days as he attempts to get the swelling down. He's also battled a shin injury recently. The Heat have hinted they'll be cautious with Andersen and almost didn't bring him on the trip to Indiana.
"I feel better, we'll just have to see," Andersen said Wednesday. "I'm just getting treatment and trying to be smart about my injury."
Andersen has averaged 6.7 points and 7.7 rebounds per game off the bench in the series and has been the Heat's most reliable defensive option in the post against the bigger Pacers front line. Allen is averaging 10 points and 3.5 rebounds while shooting a team-best 44.4 percent from 3-point range against Indiana.
"He's the human bruise, so he has a lot of different things going on all over his body, and he's been able to play through all of that," Heat coach Erik Spoelstra said of Andersen. "He's a tough guy. We all know that. He plays through pain. But you have to understand the difference between pain and injury."
Regardless of the Heat's available depth, Spoelstra said Miami is prepared to face a Pacers team desperate to avoid elimination. The Heat are a victory away from advancing to the NBA Finals for the fourth consecutive season as they pursue a third straight title.
"Naturally, you're going to get incredible urgency coming from their side," Spoelstra said. "Their backs are against the wall, and that's the only thing you have left is to play as if you have no tomorrow. And that's something you not only have to try to match, you have to try to exceed it."
ESPN.com's Brian Windhorst and The Associated Press contributed to this report.