The England international picked up the ligament damage in the club's 2-1 loss against Bolton Wanderers on Wednesday.

Moyes initially predicted the former Sheffield United centre-back will be 'probably out for up to six weeks' and admitted the loss of their vice-captain is a major blow.

"Jags has got medial ligament damage," Moyes said on Friday.

"Losing Jagielka is an incredibly big thing for us because the one thing about the team at the moment is they have been very strong defensively in the main."

"Whether it has been Jagielka with Sylvain Distin or John Heitinga that has worked really well for us."

"To lose him is a massive blow to us because he is an integral part of the defence and very important to us."

Jagielka joins a growing injury list at Goodison Park, with Leon Osman and Tim Cahill among the players currently sidelined for the Toffees.

"Leon Osman has a floating bone in his knee which we think will have to be taken out and we have a few other injuries kicking around as well - Tim Cahill, Ross Barkley (knee) and Jack Rodwell (hamstring)."

"Jack's had a recurrence of his hamstring injury. It is not serious but every time we get him scanned it is a grade one and very light and he comes back and doesn't feel anything."

"We maybe just need to give him a week or so longer to make sure he is right this time."