Everton manager Roberto Martinez has said that the club are planning to assess the extent of an injury to Kevin Mirallas.
The Belgian was replaced in the second half of the club's 2-2 draw with Watford after a challenge from Valon Behrami.
"He wanted to stay on the pitch, clearly," Martinez told the club's official website. "But he had a really nasty tackle and we're going to be assessing him in the next 48 hours.
"He tried to stay on, he couldn't and now we'll see what the extent of the injury is."
Miralles had signed a new three-year contract with the club on Friday, after intense speculation over his future.
Martinez has also said that he expects Leighton Baines to be out of action for a long spell.