Chelsea remain hopeful Thibaut Courtois will be available for their FA Cup semi-final against Tottenham on Saturday.
The Belgium goalkeeper missed their Super Sunday defeat away to Manchester United due to an ankle injury.
Sky Sports News HQ understands Courtois sustained an ankle problem while playing basketball in a commercial shoot, with the 24-year-old replaced in the starting line-up by Asmir Begovic.
Chelsea will not confirm how Courtois picked up his injury and head coach Antonio Conte told Sky Sports: "I think it is not important now to understand the way that he had this injury.
"The bad news is that he is injured and now it is important to work to recover very soon.
"Thibaut Courtois for sure is one of the best goalkeepers in the world, but we trust a lot in Begovic."