Embiid, 31, didn't take part in the 76ers' Saturday practice, and the team said he had increased soreness in his right side after he was injured in Thursday's home win over the Miami Heat.
Embiid was hurt in the first half but finished the matchup against Miami with 26 points and 11 rebounds. He hit a game-sealing three-pointer with less than 30 seconds remaining.
The Sixers said an MRI exam revealed the strain. Embiid will miss Sunday's game against the Celtics in Boston and games against the San Antonio Spurs and Utah Jazz before he is reevaluated.
The Cameroon-born star, who won 2024 Olympic gold with the United States, has dealt with a raft of injuries in his NBA career.
He returned on Tuesday after missing five games with a stress reaction in his right shin and for continued management of nagging knee trouble.
He has had multiple knee surgeries and played in just 19 games last season after missing significant time in the 2023-24 campaign.
Rookie teammate FJ Edgecombe said Embiid's effort in powering through on Thursday showed he wanted to be on the floor with his teammates.
"The media make it seem like he don't want to play basketball," Edgecombe said. "Like, come on. He's out there in pain, and he made a big shot at the end of the game. He barely could raise his right hand up. But that shows his character, too. He cares about winning."
Embiid's latest absence comes as the 76ers are hanging on to sixth place in the Eastern Conference, one and a half games in front of Orlando for the final direct entry berth to the playoffs.
They are without nine-time All-Star Paul George until March 25 as he serves a 25-game suspension for violating the NBA anti-drug program by taking an improper medication.