BOSTON -- While the Boston Celtics suffered a 129-119 loss to the Portland Trail Blazers at TD Garden on Sunday night, of far greater concern was the status of All-Star guard Jaylen Brown after he limped off the court without putting any weight on his right leg after awkwardly colliding with fellow All-Star Jayson Tatum with 40.4 seconds remaining in the game.

Brown, who had 16 points, 11 rebounds and four assists in 35 minutes Sunday night before the injury, stayed down on the court in obvious pain for a short time, and then got up and immediately hopped off the court and back to the locker room.

"I don't have any update on them," Celtics coach Brad Stevens said of both Brown and Tatum, saying he knew only that both of them were being looked at by the team's doctors after the game.

Tatum, however, talked to the media after the game and said he was feeling OK.

"I should be good," said Tatum, who followed his career-high 60-point performance Friday night against the San Antonio Spurs with 33 points in 37 minutes Sunday night, adding that he hoped Brown was all right. "We'll see how I feel tomorrow."

The late injuries to Brown and Tatum overshadowed a wildly entertaining game in which both teams shot 50% or better from 3-point range, with Portland (36-28), now winners of four straight, getting 33 points from CJ McCollum and 26 from Damian Lillard.

During the fourth quarter, however, two plays helped swing the momentum in Portland's favor: a goaltending call on Tristan Thompson on what appeared to be a good basket with 7:27 remaining, and Marcus Smart being ejected with 1:56 to go after hitting Jusuf Nurkic in the groin.

Stevens said after the game that he was told he didn't challenge the call in time -- something referee Sean Wright, the crew chief for Sunday night's game, confirmed in a postgame interview with a pool reporter.

"During live play the ball was touched by Thompson and it was deemed to be in the cylinder at that time," Wright said, in explaining why the call was made.

"The challenging team must call a legal timeout and signal for a coach's challenge. When Coach Stevens calls a timeout, the ball was already put in play with Portland having possession therefore we could not grant Boston a timeout."

As for Smart, Wright said his contact with Nurkic, who was called for an offensive foul on the play, was deemed unsportsmanlike, thus earning Smart the sixth ejection of his career.

"That was a physical play," Stevens said. "I haven't seen the replay yet. I'll look at the replay and then we'll address that internally. But obviously that's a big play at a big moment."

Meanwhile, Evan Fournier, who has struggled mightily since returning from a positive COVID-19 diagnosis, scored 21 points on 8-for-10 shooting, including going 5-for-7 from 3-point range.

Fournier, who had made a total of eight shots (and four 3-pointers) in the five games he'd played since returning to the court on April 23 (he shot a combined 8-for-37 overall and 4-for-21 from 3) said that he felt like he had a concussion in the wake of his positive diagnosis and that it had impacted his vision and depth perception.

"I've been feeling really weird, to be honest," Fournier said. "My plan was to stop talking about it so it might help me, but the thing is it's like I have a concussion. Right now it's actually doing a little bit better, but at first the bright lights were bothering my eyes and my vision was blurry.

"Everything was just going too fast for me. It's still the case. Some stuff is better, but at times I'm really struggling to focus and my eyes keep struggling focusing on one thing. My depth perception is really bad right now. But I saw a specialist and she gave me some exercises and hopefully it'll get better."

Fournier, whom the Celtics acquired at the trade deadline using the trade exception generated when Gordon Hayward signed with the Charlotte Hornets in the offseason, said that while he wasn't 100 percent, the fact he was physically healthy meant he felt he needed to be on the court with his new teammates.

"I mean, that's the thing," Fournier said. "With this COVID thing, the truth is doctors and everyone, they really have no idea. It's so new. But the stuff that I'm feeling, apparently one-third of the people after COVID got those symptoms as well. So it's not an isolated case. But like I said, with time it's going to get better. Some people lost their taste of the food, and the smell. For me it's just my awareness and all that. It's a part of the senses. But it's going to get better. It's already slightly better. But I'm going to keep working. I can't just take games off or practices off because I'm not feeling well mentally. If my body's available I have to be available."