Everton manager Roberto Martinez has revealed that Phil Jagielka will undergo a second scan on a hamstring injury.
The England international is a doubt for the Toffees' FA Cup semi-final in 12 days' time as he has already been ruled out of this week's Premier League matches against Crystal Palace and Southampton.
Jagielka suffered the blow in the final minute of last Saturday's 1-1 draw with Watford at Vicarage Road.
"Because we scanned it really early, just to try to see if we could use him straight away, the information is not very clear," Martinez told reporters.
"We need to allow it to settle down. What's clear is that he can't be working or exercising until Monday and then we will assess him, we will re-scan him and have a clear idea of the extent of the injury at that point."
Everton will face either Manchester United or West Ham United in the semi-finals.