There’s no easy answer at center for the Celtics this season, and Brad Stevens says the starter could change from game to game depending on the challenge posed by a particular opponent.

Based off the Celts’ defensive success in weekend preseason wins over Orlando and Cleveland with Daniel Theis starting, he appears to have the inside track on the job.

But even Theis knows he didn’t get the most difficult potential tests the last two games.

“When I started in Orlando, I was looking forward to going against (Nikola) Vucevic, because, I mean, he is one of the top centers to see better down there because he’s a great post-up player,” Theis said. “He didn’t play and also (Sunday) I was looking forward to Tristan Thompson (of Cleveland, who was out with an injury). He’s one of the best defensive rebound centers in the NBA, so he’s strong.

“So we’ll see how this works out. It’s going to be hard playing against those guys, especially for me. Philly will have Joel Embiid down there. When I play 5, we’ve got to do it as a team effort. Playing those guys one-on-one is tough for everybody in this league, so we’ll see how it goes.”

Theis indicated he’s more prepared for the job in his third NBA year.

“I learned a lot from Al (Horford) and Aron (Baynes) over the last two years, especially on the defensive end,” he said. “Just to be in the right spots in the pick-and-roll. Also coaches helped me a lot over the summer, just in putting myself out there where I’m good, on the ball in pick-and-roll where I’m not so good.”

Their time to shine

It’s looking like a bullpen game of sorts as the Celtics close out their preseason slate against the Cavaliers. On who will be playing, Stevens said, “It’ll be some of the guys that played a little bit less the last few games.”

Jayson Tatum (illness) missed Monday’s practice and didn’t make the trip to Cleveland. Romeo Langford (knee) also didn’t go through the workout and won’t play Tuesday, but he is on the trip.

In terms of a prognosis on Langford, Stevens said, “I haven’t gotten anything like two weeks, three weeks. I haven’t gotten any timeline on it. I just know not (Tuesday).”

The coach is being cautious when discussing the Celtics’ defense. After a bad outing against Charlotte, the C’s picked up on that end, allowing the Magic 75 points and the Cavs 72.

“I thought the way we guarded in Orlando set a nice tone for the rest of our weekend, but, you know, I’m always hesitant to talk too much about it, because you have to choose to do it every day,” Stevens said. “The good news is we’ve shown ourselves capable. That’s what I’m encouraged by.”

He is wary, too, of reading too much into these games overall.

“I just think you have to build habits,” Stevens said. “Nobody in here really pays attention to the scores and all that stuff, but you can pay attention to the habits you’re building and how you’re playing. One of the things that I thought we weren’t good last year was our preseason, and I think that was pretty well-documented.

“I feel good about the direction we’re heading now and how many good days we’ve had out of the first few weeks. It doesn’t mean you’re going to be perfect, but there’s been a lot more good days. There’s a lot of good intent, and we’ll just keep building on it. The schedule is tough early, so I think we just know that. But we’re getting ready to play an 82-game season, not a 10- or 20-game season. And I feel good that we’re building good habits.”

Getting used to it

Kemba Walker is taking well to the new surroundings, especially the quality of his new teammates.

“It takes a lot of pressure off me,” he said. “I’m getting a lot of different shots, as well, but I’m loving it, not having not do so much all the time. Hopefully my usage rate might be going down a little bit. It allows other guys to make plays, and I can appreciate that for sure.

“We just have so much talent around us, and just not having to do so much. I’ve done a lot over the course of my career.”

Done with preseason

Stevens is happy to get the preseason games out of the way. The Celts will take Wednesday off, practice the next three days, then take another break before returning Monday to prepare for the season opener in Philadelphia a week from Wednesday.

“So we do have, I think, five practices before our first game,” he said. “It gives you a chance to clean up stuff you need to clean up. If you want to add something for your opponents that are coming up, you can do that. You’ve got all kinds of flexibility with that. If you’re playing a game on Friday and Sunday, it may be a little bit more difficult to do some of that.”