After left wrist surgery ended his season ended prematurely last May, Jaylen Brown returned to the court for the Celtics with a fervor

Jaylen Brown was impressive in Monday's preseason win over Orlando.Matthew J Lee/Globe staff

It was apparent early in the Celtics’ preseason opener against the Orlando Magic that All-Star forward Jaylen Brown was playing with extra motivation and fervor. This was no ordinary meaningless preseason game. He badly wanted to play and flourish after five months away from basketball.

His season ended prematurely in May following a left wrist injury that required surgery, the first time he’s had any surgical procedure in his career.

The recovery was expected to last into perhaps the regular season, but Brown was cleared for full contact before training camp and there were no signs of rust or hesitation. He scored 25 points in 26 minutes in the Celtics’ 98-97 comeback win at TD Garden.

The overall team review after the opener was subpar at best. The Celtics overpassed, struggled to score and committed too many turnovers. Jayson Tatum was blitzed at the 3-point line and forced into dribble penetration or swinging the ball to teammates.

Brown, however, looked as if he was ready to take the next step after his first All-Star appearance. He splashed threes, attacked the rim and used his dribble to create space for mid-range jumpers. The Celtics are going to need a better Brown and better Tatum to compete in the Eastern Conference.

Right now they are projected as a fifth or sixth seed, but with all their new pieces, including Dennis Schröder, Josh Richardson, Al Horford, Juancho Hernangomez and Enes Kanter, the Celtics could make a run.

Yet, the first step in that process is ensuring that Brown is completely healthy and ready to impact on offense and defense.

“It was fun,” he said of his first game since May 2. “I haven’t been on the court in a while. Just getting out there in front of the home court was really great. The playoffs were really hard for me to watch but I’m back, I feel great and I’m ready to play some good basketball.”

Brown chose to have wrist surgery in May and begin rehabilitation immediately instead of allowing it to impact games this season. He reported himself about “80 to 85 percent” with some expected soreness postgame. But the fact Brown is healthy and playing at this point was the most positive development of training camp so far.

“[The wrist] held up pretty good,” he said. “At times it bothered me a little bit, but I’m going in the right direction. Today was a good test.”

It was difficult summer for Brown, who was denied basketball for the first time in his life. The injury prevented him from trying out for Team USA, a team he mostly certainly would have made if he were healthy. And he had to watch the Celtics’ first-round series loss to the Brooklyn Nets from behind the bench, knowing he could have affected the series or at least helped the Celtics extended it beyond five games.

But his rehabilitation was much faster than expected. He capped his offseason with a workout at his Cal alma mater with the men’s basketball team. There would be no training camp delays or time missed. Brown was ready to return.

Jaylen Brown looks to pass in the second half of Monday's preseason win.Charles Krupa/Associated Press

“Right now I think I’m still ahead of schedule,” he said. “Hopefully there’s no setbacks. One time, I think I got hit and it hurt a little bit, but the pain kind of wore off. I’m just going to stay with the routine. I mean, it’s not going to be perfect, but I think that I’ll be fine.”

Brown said the idle time enabled him to watch basketball games and digest them from a different perspective. He said extra research was helpful.

“When you’re forced to watch the game, you’re forced to look at it from different angles,” he said. “The game just looks different for me now. I don’t know how to describe it. It doesn’t look the same. I spent a lot of time watching [games], watching film and now that I’m back, the game definitely feels different, in a good way.”

Brown realizes the Celtics’ defense slipped considerably last year and a point of emphasis under Udoka’s regime is getting back to those defensive principles. The Celtics have enough athletes and defensive-minded players with their new additions to become one of the better teams in that category.

“I demand more of myself on the defensive side of the basketball; I demand more from [Marcus] Smart, even though he’s all-defensive [team], to be more of a leader, talk more,” Brown said. “I’m all focused on defense. I think on offense we’ll get shots. All of that stuff will take care of itself. We’ve got a lot of crafty guys who can get that ball moving.

“I think we’re going to get what we want on offense. I just think defense is where we’re going to make an impact this year. If we make an impact on defense, I feel like we’ve got a shot to be a really good team.”