Everton boss David Moyes has expressed his concern over Jack Rodwell's fitness after he suffered another setback.
The 20-year-old had completed an extensive rehabilitation programme after he aggravated a hamstring injury and was due to return this weekend.
However, the midfielder suffered a reaction after training on Thursday and, although the scan results are not confirmed yet, Moyes has admitted that he is worried by the player's fourth hamstring problem of the season.
"It is a big concern," said the Everton manager.
"He has done lots of extra work, lots of strengthening. He has had a week and half of football training. We were going to play a practice match here and I was going to maybe play him in that. Maybe it's not too bad. We don't know yet.
"He trained on Thursday and just told us this morning that he felt it. We have given him five or six weeks to get over this and we will check it again. We have done everything we have thought we needed to do but it looks like he will be out of action."
If the injury is serious, Rodwell will also miss England's friendly against Holland later this month.