WALTHAM, Mass. — Chemistry is tough to predict.

It takes some teams weeks to click, some months, and some never do.

The 2016-17 Celtics have only taken the court for three exhibition games, but they believe they’ve already got some chemistry brewing.

“It’s just our mindset going into each game,” Avery Bradley said. “Trying to move the ball, play basketball the right way. Making the extra pass, and it’s helping us out a lot. It’s making us look like we’ve been playing together for a while. It’s fun basketball.”

The starting five of Bradley, Isaiah Thomas, Amir Johnson, Jae Crowder and new guy Al Horford impressed in the first two contests, despite their relative unfamiliarity. With Horford on the court, the Celtics outscored their opponents by 39.

Thomas credits the brand of basketball they’ve been playing.

“Our pace and our unselfishness,” Thomas said. “We’re looking to not just get a good shot, a great shot. And the ball is just going side to side. I think it’s not holding it, staying in one place. It’s being effective. We’ve got guys out there that are just in the right spots.”

He hasn’t been around long, but Horford is already one of those guys.

“Al, you put him anywhere and he’s going to figure it out,” Thomas said. “He’s always in the right spots, and I keep saying that, but I don’t think coach has told him he’s in the wrong spot since he’s learned the plays.”

Thomas has been playing off the ball more than he’s used to, as Horford is one of the few bigs in the NBA with the unique talent to grab a rebound and then take it coast-to-coast.

“I’ve just got to get used to that,” Thomas said. “I haven’t really had a guy, other than (Sacramento’s) DeMarcus Cousins, that can get the ball and go all the way down and make a play for himself – or make a play for somebody else.

“That’s a skill that he really has and it’s special, because he’s not just looking for the guards. He’s really looking to push it himself, and we’ve just got to learn to run the lane.”

• Jordan Mickey scored 16 points and grabbed six rebounds Saturday in Boston’s 104-86 preseason win over Charlotte at Uncasville, Connecticut.

The Celtics outscored Charlotte 64-46 in the second and third quarters. Tyler Zeller finished with 14 points and Gerald Green added 13 in his preseason debut.

Thomas didn’t play because of a sprained wrist from Thursday’s 107-92 win over Charlotte.

“I’m good. It wasn’t swollen so I’m all right,” Thomas said. “I iced it a lot (after the game), wore a wrap on it on the plane, so I’m fine.”

CLIPPERS: Rookie forward Brice Johnson suffered a herniated disk in his lower back in Thursday’s preseason game against the Toronto Raptors and is out indefinitely.