Chelsea defender Kurt Zouma left Sunday's match against Manchester United on a stretcher after landing awkwardly on his right leg and appearing to damage his knee.
Zouma, who didn't collide with anyone, jumped for a loose ball before he collapsed to the ground with what looked like a serious injury. He could be heard screaming as he laid down writhing in pain.
Gary Cahill replaced Zouma in the 59th minute.
The 21-year-old has emerged as one of Chelsea's primary centre-backs over the course of a trying season, making 21 Premier League starts out of a possible 25.
