A right hamstring strain sent Brown to the bench late in the first half of Saturday night’s Game 7 victory over the Milwaukee Bucks and may keep him out of the opener with the Philadelphia 76ers Monday night.

Jim Fenton The Enterprise @JFenton_ent

WALTHAM – He was the Celtics’ second-leading scorer in the opening round of the playoffs while starting for the first time in the postseason.

Jaylen Brown gave the Celtics 17.9 points per game and was second on the team with 17 3-pointers, helping them get by the Milwaukee Bucks in seven games.

But when the Celtics open the second round on Monday night against the Philadelphia 76ers at the TD Garden, Brown may not be available.

Following a film session Sunday afternoon, coach Brad Stevens listed Brown as “doubtful’’ for Game 1 because of a strained right hamstring, an injury that occurred late in the first half of Game 7 Saturday night.

Brown had some tests done on the hamstring that were negative, but there is still soreness and the Celtics may want to give him some time to rest before Game 2 on Thursday night.

“The last email I saw (from the medical staff) was that he still had some soreness, didn’t try to do anything that I know of running wise today, did have some testing and that looked good, thankfully,’’ said Stevens. “Doubtful for tomorrow, but I guess he could play. It looks like it could be something that allows him to play as the series goes on.’’

The Celtics are going to need size and versatility on defense against Ben Simmons and the Sixers, so not having Brown would be a significant loss.

Stevens said he would come up with a starting lineup Monday morning, and it could include the return of Aron Baynes, who came off the bench the final three games against the Bucks with Semi Ojeleye starting, Marcus Smart or Shane Larkin.

Already missing Gordon Hayward, Kyrie Irving and Daniel Theis, the Celtics are probably going to have to deal with another absence.

“It is what it is,’’ said Baynes. “You’d definitely love to be able to have the team that you started off training camp with, but it’s not going to happen. It rarely happens that you can do that.

“That’s why we’ve been so good this year because everyone understands their role. You’ve got to come in and fill that role. We play as a team and that’s what makes it so much fun. We understand that we have that next-man-up mentality. Everyone understands the next guy that is going to be called upon from the bench has the ability to come in and do the right things and affect the game in a positive way.’’

Homecoming for Morris: Celtics forward Marcus Morris grew up in Philadelphia and was a big fan of Allen Iverson when he was a youngster. Now he gets to return home to face the Sixers in the playoffs.

“I think I’m going to be a little nervous playing in front of the people I was raised in front of, being able to go back all grown up with the Boston Celtics,’’ said Morris. “It’s going to be a little nerves at first.

“I expect it to be the same treatment as far as people not caring I’m from Philadelphia. I’m going to have my own personal fans -- my family, people who watched me grow up. I know so many people out there who watched me and my brother (Markieff) grow up, but they’re also die hard Philadelphia fans.’’

Quick turnaround: After finishing the series with the Bucks Saturday night, the Celtics have less than 48 hours to get ready for the Sixers, who have been idle since Tuesday night. Philadelphia eliminated the Miami Heat in five games.

“It’s difficult, but we’re not complaining,’’ said Al Horford. “We’re in the next round, we’re excited and we have a good opportunity in front of us.’’

Horford averaged 35 minutes in the Bucks series but said he is ready to play long minutes.

“I tried to do everything I could to recover and be as fresh as I could for the games,’’ said Horford. “This round is not going to be any different. You recover as quick as you can. That’s the name of the game at this point.’’

The Celtics will have two days off after Game 1 with the second game Thursday at 8:30 p.m. The games in Philadelphia next Saturday and Monday will start at 5 and 6 p.m., the NBA announced on Sunday.