Whatever happened to the Celtics’ fast break?

Celtics coach Brad Stevens is concerned the team is not converting in transition. Jim Davis/Globe Staff/File 2016

MIAMI — Last season the Celtics continued to build their identity with a fast-paced approach that was usually sparked by their defense.

But so far this year they have not been as reliant or effective with their push-the-ball approach. Last season, 15.4 percent of the Celtics’ points came on fast breaks, the sixth highest mark in the league. Entering their game Monday against the Heat, just 10.8 percent of their points had come on breaks, ranking 23rd. And that figure will only plummet after their 112-104 win in which they had just 5 fast-break points.

Not only are the Celtics running less, they are not capitalizing often when they do push the pace. Boston’s 47.4 percent score frequency on fast breaks ranks 23rd in the league, too.

“If you look at our offensive numbers right now, the only area I’m concerned about is that we’re not converting in transition,” Celtics coach Brad Stevens said. “When we’re in the halfcourt, we’ve been OK and we’re shooting it fine, all those types of things. We’ll see what it all looks like after 80 games, but the transition efficiency is not very good.”

The Celtics are forcing 14.3 turnovers per game, 2.1 less than they did last season, and Stevens said part of the slowdown can be attributed to Jae Crowder’s eight-game absence with a sprained ankle. Stevens said the Celtics worked on advantage situations often in practices, such as two-on-one or three-on-two breaks. He said it is also important for players to get to the right spots on the court during these breaks.

“Sometimes you have a matchup that you feel like you can beat down the floor,” he said. “Sometimes you get one of those runs of basketball that happens where you’ve got five or six straight possessions that go your way. Overall I’m less concerned about the idea of running and more concerned about our efficiency when we do run. That’s where we’ve been a little bit short.”

Big expectations

Celtics forward Al Horford missed Monday’s game for personal reasons, Stevens said. The four-time All-Star is expected to rejoin the team in Boston on Tuesday. In a post on her Twitter account on Sunday, Horford’s sister, Anna, said: “My niece has arrived!!”

Horford and his wife Amelia have been expecting their second child, a baby girl. Horford returned to the Celtics’ starting lineup on Nov. 19 after missing nine games with a concussion. This season he is averaging 14.7 points, 6.9 rebounds, and 2.6 blocks per contest.

The Heat were hardly at full strength on Monday night. Miami was without Justise Winslow (wrist), Dion Waiters (hip flexor), and Tyler Johnson (oral surgery).

Warm weather boost

Crowder has been on a minutes restriction as he works his way back from a sprained ankle. But it appears that will soon be completely lifted. Stevens said he would not hesitate to play Crowder longer than 25 minutes on Monday, and sure enough, Crowder played 31 minutes, the most since his return. He finished with 17 points and 4 rebounds.

Crowder said being in Florida’s warm weather over the past two days has helped his ankle, and that he is feeling better.

“I do feel like it’s close to an end,” he said of having his playing time limited.

Green is patient

Celtics forward Gerald Green averaged 22.6 minutes per game for the Heat last season. He signed a one-year deal with Boston last summer, but entering Monday he had appeared in just 10 games, averaging 10.9 minutes per contest.

Stevens affirmed on Monday that there will be a time this season when the Celtics need Green. Green, meanwhile, is remaining patient.

“I’m not gonna lie; it’s tough,” he said. “But enjoying somebody else’s success is a huge part about being a professional. And I think right now the way we’re playing, we’re playing good basketball right now . . . For me to sit here and pout about not playing would be selfish and not being a good teammate. Don’t get me wrong; I’m a competitor and want to play, but I think that if I just stay ready, stick with my workout and stuff like that, my time will come.”