O'Neal is probable for Game 3

Tomorrow night, the Celtics expect Shaquille O’Neal to return to the court, for Game 3 of the Eastern Conference semifinals against the Heat.

The Celtics, who lost Games 1 and 2 in Miami, watched film yesterday but didn’t hold a formal practice. The second unit conducted drills but the starters had a light day on the court.

“Right now, we expect every single guy, including Shaq, to play,’’ said coach Doc Rivers.

O’Neal has played in only one game (for five minutes) since Feb. 1 because of Achilles’ tendon and calf injuries.

Each week, the progress report on O’Neal has included improvements, with hopes he would be available in the postseason. But for one reason or another, the return date has always been pushed back.

Before Game 2, O’Neal participated in his first practice since injuring his right calf April 3.

This time, Rivers said, trainer Ed Lacerte is optimistic O’Neal will be ready to play at least a few minutes tomorrow night.

“I do expect him to play, but if he didn’t play, it would be because something went wrong at practice,’’ Rivers said. “But right now, I expect him to play.’’

After Game 2, Rivers said he didn’t know who was healthy and who wasn’t among his starters. O’Neal’s progress was the last thing on his mind. Paul Pierce strained his left Achilles’ tendon in the first quarter. Ray Allen suffered a bruised chest when he took an elbow from LeBron James. And Rajon Rondo was experiencing discomfort in his back.

Yesterday, Rivers said, “Everybody’s feeling pretty good.’’

It can be done Glen Davis gained inspiration from talking with Celtics legend John Havlicek at practice. “I said, ‘Which one of these banners was 0-2?’ ’’ Davis said. “The one that stood out to him was ’69. They were down, 0-2, they came back to win it then, in Game 7 against the Lakers. He was just saying it’s going to take everything in you to fight and claw back, to get back to that 2-2. Then, it’s going to take something special to finish them off.’’

A lot on their mind Rivers gave the players Wednesday off, but he doesn’t know that all of them took much of a break. “I think a majority of guys watched the game a couple of times over, which is good and bad, I guess,’’ Rivers said. “Other guys just kind of took a mental break.’’ The players are aware of the challenge facing them. “[We feel] the way you would feel if your back was against the wall,’’ Davis said. “As a player, you would do anything possible to get off the wall, right? Think about all those emotions you have — frustrated, mad, want to help, want to be the hero, want to do this, want to do that. That’s what everybody wants — to win, point blank. Frustration, things not working out, you can get all messed up.’’

Frank Dell’apa of the Globe staff contributed to this report. Monique Walker can be reached at mwalker@globe.com. Follow her on Twitter @monwalker.