Not that he knew Jermaine O’Neal would be damaged goods, with a left knee that has caused him to miss 34 games this season. But Ainge astutely prepared for the possibility that each of the big men would endure some type of ailment.

Erden is playing with a left shoulder that will require surgery in the summer, and has had a sore groin. Perkins just returned after missing the first 43 games of the season following knee surgery in July.

And Shaquille O’Neal has missed 12 games with various injuries, including a sore right hip that has cost him the past three games.

Yet the Celtics entered last night’s matchup with the Portland Trail Blazers with an Eastern Conference-best 34-10 record despite those issues in the middle.

“We’ve needed everybody,’’ Ainge said. “And everybody’s contributed. We’ve had injuries everywhere and we’ve been fortunate.’’

Perkins’s return helps stabilize the position and allows coach Doc Rivers to temper his expectations for Shaquille O’Neal. There was a perception among some when Shaq signed that he would make demands such as starting, getting significant touches, and playing in the fourth quarter.

But he has made things simpler with his low-maintenance attitude and fully realizes that although he is capable of occasional dominance at age 38, his body is no longer the V-8 engine that can gobble up miles without a trip to the mechanic. O’Neal’s body now needs rest after nearly every setback, which is something Rivers expected.

O’Neal has played 80 games a season twice — the first two seasons of his career. Since 1994-95, he has played in just 73 percent of his team’s games; he has played in 73 percent of the Celtics’ games this season.

“Unfortunately, my last 10 years, I haven’t played 82,’’ he said. “I’ve been out with knick-knack injuries, but the good thing about this team is we got a lot of bigs. So I don’t really have to try to be the hero. So when I get close to 80 percent, I want to be back out there with the guys.’’

Said Ainge, “He’s played great. We knew he wouldn’t be playing 80 games and there would be some times he would take off. Again, we’re happy with the way our guys have played. Those guys by committee have held down the fort at the center position.’’

O’Neal’s longevity is amazing in itself, considering he is the only player left in the NBA from the 1992 draft — and the only one left who played in the 1993-94 season. At 325 pounds, O’Neal still appears rather nimble and spry for his size and age, and a recent alley-oop from Paul Pierce that had him soaring for a one-handed dunk is proof that the raw athleticism remains.

“The good thing about me is, my game has always been the same,’’ he said. “And it’s always going to be like that. I’ll be ready. I came here for a reason, and hopefully we can get it done.’’

Boston’s front office did not expect O’Neal to approach 82 games, and the downtime is preserving his body for the second half.

Ainge did not expect the rapid development by Erden (though he still causes Rivers to look at his assistants in amazement when he misses a defensive assignment or sets a poor screen).

Erden has emerged as a capable starter and adequate fill-in for Shaquille O’Neal. Ainge worked to bring him over from Turkey because he was a big body, but he has proven more NBA-ready than expected.

“He’s had ups and downs, like all rookies, but he’s an experienced pro player [internationally],’’ Ainge said. “He’s not like all rookies. He’s played against good competition.

“Even though the NBA game is different and it’s different competition, he has the language barrier and everything else rookies don’t have, he’s been great, all told. We’re sure glad we have him.’’

Rivers never harbored any concerns about minutes, roles, or egos. He left that to the fans. He hopes the second half of the season brings more normalcy regarding injuries, but the depth certainly helped make the first half a successful one.

“I would prefer to have them all,’’ Rivers said. “Then we could rest guys and we could do a lot of other things.

“Right now it’s working out that we have enough bigs. But I’m looking forward to the day where [having too many] becomes a problem. That would be great.’’

Gary Washburn can be reached at gwashburn@globe.com.