WALTHAM, Mass. — Boston Celtics guard Jaylen Brown is doubtful for Game 1 of the Eastern Conference semifinals against the Philadelphia 76ers with a strained right hamstring, Coach Brad Stevens said Sunday.

Stevens added that Brown could return later in the series.

Stevens said Brown still had soreness Sunday, a day after the Celtics eliminated the Milwaukee Bucks and a day before the second-round opener. Brown had said he was going to have an MRI and Stevens said tests were negative.

“It looks like it could be something that allows him to play as the series goes on,” Stevens said.

Brown, the No. 3 overall pick in the 2016 draft, averaged 14.5 points and 4.5 rebounds per game this season. He left Saturday night’s clincher against the Bucks in the first quarter; the team announced that he was available to return but Stevens decided to play it safe.

Brown said afterward he was told it was a Grade 1 injury – the least severe kind. He was put on anti-inflammatory medication.

“Whatever it takes, I wouldn’t miss this series for the world,” Brown said Saturday night.

The Celtics are already without standouts Gordon Hayward and Kyrie Irving, as well as Daniel Theis.

“We don’t think about what’s happened throughout the season,” center Aron Baynes said. “We have that ‘next man up’ mentality. We’ll miss Jaylen; he’s definitely hard to make up for. It’s just all being able to collectively do it.”

So much of the chatter before Boston’s first-round matchup with Milwaukee focused on who wouldn’t be on the court for the Celtics.

The injuries, which included Marcus Smart at the start of the series, seemingly left the East’s second seed vulnerable against a Bucks team boasting one of the league’s most versatile scorers in Giannis Antetokounmpo.

It took seven games but the Celtics got just enough from their healthy players to hold off Milwaukee with a 112-96 victory Saturday night. Now they’ll turn their attention to Ben Simmons, Joel Embiid and another young team against Philadelphia.

“It’s something we’ve had to go through all season,” said rookie Jayson Tatum, who had 20 points Saturday, becoming just the second rookie in Celtics history to score 20 in a Game 7. “Some way, somehow, we figure it out. And I think that’s what’s unique about our team.”

Tatum is one of the young Boston players who have grown quickly over the past three weeks. Because of it, the Celtics have squeezed out their best basketball despite the multiple subtractions to their roster.

Terry Rozier put up career numbers after stepping into a starting role. Smart injected life into the team over the last three games following his return from thumb surgery. And rookie Semi Ojeleye made things difficult for Antetokounmpo.

Al Horford provided not only his voice but probably his best stretch of games in a Celtics uniform over the last seven games. He matched his playoff career high with 26 points on 13-of-17 shooting in Game 7, and averaged a team-high 18.1 points and 8.7 rebounds for the series.

“It’s what I think I’ve been doing all year,” Horford said. “It’s what we’ve been doing as a group. We didn’t treat this any differently. … I felt like our guys, their poise was great. Milwaukee fought hard. They kept giving us shots, our guys stayed with it and eventually we wore them (out).”