BOSTON — Though Jayson Tatum returned to the Boston Celtics’ lineup two months ago, his body has yet to fully recover from the Achilles surgery he underwent last May.

That rehab process, he said, still is ongoing. This weekend, it hit its first setback at “the worst possible time.”

Stiffness in Tatum’s left knee — the opposite leg from the one he injured in last year’s Eastern Conference semifinals — prevented him from suiting up in Game 7 against the Philadelphia 76ers on Saturday. The short-handed Celtics lost 109-100 at TD Garden, capping a three-game losing streak that ended their season.

“I just experienced some tightness back there,” Tatum, who watched from the bench in a gray jumpsuit, explained Sunday. “It was just unfortunate timing, but I guess a little bit to be expected. I was away for 10 1/2 months, and then I came back and I’m playing every other day, and I was playing 36 to 40 minutes. So it’s not unusual that something would come up.

“It was just kind of tough because rehab was just going so well the entire time. I guess it was inevitable at some point that I was going to have to deal with something. And it just kind of came at the worst possible time.”

Tatum dealt with left leg discomfort during Boston’s Game 6 loss in Philadelphia, but he and head coach Joe Mazzulla downplayed that issue during the lead-up to Saturday’s finale. Both said they expected Tatum to be available in Game 7. The Celtics did not list him on the injury report they released Friday afternoon.

But Tatum was downgraded to questionable Saturday afternoon, then ruled out less than two hours before tipoff. Mazzulla said he and the Celtics’ medical staff decided it “was in (Tatum’s) best interest” for him not to play.

“They just kind of assessed everything that was going on,” Tatum said. “And I’m still in the window. I was in the window of return-to-play protocol, and there were just certain rules and a plan that, ultimately, that we had to stick by. And it was tough, obviously, working as hard as I did to come back and to be available and for it to come to a Game 7, not be able to be out there. I just keep saying this was unfortunate and it’s tough to deal with, but it’s a plan that we have to stick to.”

For Tatum, it was a gut-punch end to a season with storybook potential. After missing Boston’s first 62 games, he returned in early March and almost immediately began playing at an All-Star level. He averaged 21.8 points, 10.0 rebounds, 5.3 assists and 1.4 steals over his 16 regular-season appearances — of which the Celtics won 13 — and was the team’s most consistent contributor in Games 1 through 6 against Philadelphia. His plus/minus and net rating this postseason were the best of any Celtics starter.

Tatum said he “didn’t have any hiccups the first 50 weeks” after his surgery, estimating that he played at “80 to 85%” of his potential after his midseason comeback.

“My recovery and comeback were going so well that how it ended, I didn’t think it was going to end that way,” he said. “Not necessarily regret. It was just unfortunate. I worked really, really, really, really hard to come back in the fashion that I did and play at the level I was playing at. So for it to end the way it did was a tough pill to swallow.”

Had the Celtics, who cut an 18-point second-half deficit to one on Saturday before going cold late, advanced to face New York in the East semis, Tatum is confident he would have been available.

“It was definitely a day-to-day thing,” he said of his injury. “It sounds pretty vague, but it’s just something we would have assessed from day to day. It wasn’t like a long-term thing. I know for a fact I would have been able to play if we’d have made it to the second round. We would just take it day by day.”

Despite the outcome, Tatum said he has no regrets about returning this season. He believes he “100%” made the right choice to rejoin the Celtics when he did rather than waiting until 2026-27, as fellow stars Tyrese Haliburton and Damian Lillard did after suffering the same devastating injury last postseason.

He hopes to be “a sort of inspiration” to future players.

“I’m very happy that I came back to be a part of his team,” Tatum said. “To get back to doing what I love, to help us, give us a chance to compete for a championship, to prove to myself that I can get back to being the guy who I was, and hopefully better. And just to kind of defy what this injury kind of means, not necessarily from the standpoint of, like, ‘I’m great, look at what I was able to accomplish,’ but to give other guys hope that … if you attack rehab a certain way, if you follow these guidelines, or do it a certain way, that it’s not like a career-ending injury, that you can’t come back, that you can be yourself, that you can be better, that it won’t take 18 months, that you can come back whenever it is right for you.

“So I’m happy and proud of the fact that I was able to do that. And, unfortunately, if somebody else has to deal with this, they can look at what I was able to do and have some hope and inspiration that it’s not what people used to think it was. You can come back from this and be who you were — and hopefully be better.”

____

©2026 The Boston Herald. Visit at bostonherald.com. Distributed by Tribune Content Agency, LLC.