Simmons fractured his foot on September 30, the final day of pre-season training camp.
Embiid was the third overall pick in the 2014 draft, but foot injuries kept him off the floor until this season.
Philadelphia 76ers center Joel Embiid is out indefinitely due to a knee injury and is set to undergo an MRI.
Vehicle bomb attack near al-Bab in Syria kills over 40
Last week, the Observatory reported that more than 400 al-Bab civilians had been killed in Turkish bombardments since November. Al-Tawil, a member of the opposition al-Bab military council, said about four fighters manning the checkpoint were killed.
Embiid's injury issues are compounded by the fact that the 76ers announced last week 2016 No. 1 overall draft pick Ben Simmons is out for the season with a foot injury. After such a promising January, when Embiid was playing great and the Sixers were winning games, it's been a sobering start to February for the snake-bitten Philadelphia franchise. He has continued to work out in hopes of making a return down the stretch, with the team telling reporters that Embiid was expected to miss their first four games after the All-Star break.
The Sixers said Monday Simmons was undergoing a procedure created to accelerate healing and was expected to resume training by the end of this week. The Sixers have just 24 games remaining this season.
The team updated Embiid's status Monday after he experienced swelling and soreness following recent training sessions.