BOSTON — One made shot to start the second half appeared to awaken the Celtics from their inexplicable early-season slumber in Oklahoma City.


 


Two straight wins later, they must continue to keep their groove going despite being without a key member of the rotation indefinitely.


 


Two days after Daniel Theis torched the Detroit Pistons for 17 points on 7-of-9 shooting in 19 minutes off the bench during a 109-89 victory, the reserve big [...]

BOSTON — One made shot to start the second half appeared to awaken the Celtics from their inexplicable early-season slumber in Oklahoma City.

 

Two straight wins later, they must continue to keep their groove going despite being without a key member of the rotation indefinitely.

 

Two days after Daniel Theis torched the Detroit Pistons for 17 points on 7-of-9 shooting in 19 minutes off the bench during a 109-89 victory, the reserve big man was declared out indefinitely on Monday after suffering a tear of the plantar fascia in his right foot.

 

“The indefinite timeline sounds worse than the timeline we’ve been given,” Celtics coach Brad Stevens said following a practice at the Auerbach Center. “It’s not going be season-derailing or anything like that. We’ll see how he progresses over the next few weeks and the next steps will be determined. But they think it will be a pretty good recovery, which is fortunate.”

 

Also fortunate is that center Aron Baynes is hoping to play in Tuesday night’s home-and-home rematch with the Pistons at TD Garden after missing the last three games with a right hamstring strain. Baynes said on Monday he feels “100 percent” and will be a “bull out of the gates” if he is cleared to return on Tuesday.

 

The center will be looking to reinforce the play the Celtics found within themselves starting with Gordon Hayward’s 3-pointer to spur a rally from 16 down in Thursday’s 101-95 victory at Oklahoma City.

 

“You have to go out there and believe you’re going to make those shots,” Baynes said. “I saw a little bit more belief in everyone taking their shots and that sort of feeds into everyone else. Once Gordon hit that first shot in the second half against OKC, then Kyrie [Irving] started hitting shots, Al [Horford] kept going following that same rhythm.

 

“Then it’s also locking in on the defensive end. We started playing much better defense at that point, turning teams into taking the shots we want them to take.”

 

While that 3-pointer was the only shot Hayward hit against the Thunder, he came back with his best effort of the season in Saturday’s rout as he scored 15 points on 6-of-11 shooting over 24 minutes.

 

“With each game, I am starting to remember who I was and what was going on before I got hurt,” said Hayward, who acknowledged that he is dealing with soreness in his surgically repaired left ankle that he’s been told he’ll have to expect “for a while.”

 

“I was definitely hyper-focused,” he added of the second half against OKC. “It was one of those things where we were all trying to step our energy up, get each other going. [Jayson Tatum] made a nice pass to me. So it was one of those things where were just playing together in the second half.”

 

The Celtics will look to make it three straight Tuesday night in the Detroit rematch.

 

“They are going to be different,” Stevens said. “They will make some tweaks, make some adjustments. Those are good things to have to go through that will prepare you for late in the season. They probably played their worst game up to this point and we probably played one of our better [games]. We need to be better [Tuesday] night.

 

“The response [Tuesday] is just as critical as your performance Saturday.”

 

After a ragged, 2-2 start to the season, following a lackluster preseason, that response on the road in a game that seemed to be slipping away at halftime was at least encouraging.

 

“I thought we started playing together and making better decisions,” Stevens said. “Not worrying about anything else other than about making the next right play. Then, when your shot comes, shoot it with authority. You saw it on the first possession of the second half against Oklahoma City. From that point on, we’ve played with a lot more substance than we did prior to that.

 

“There are some things that are out of your control ... but the way of playing is a conscious choice. ... We had to make a choice to be better.”