Everton will be without Jack Rodwell for up to three months after the teenager damaged ankle ligaments.
The 19-year-old midfielder missed England Under-21s' recent double-header after being injured during the Toffees' 1-0 defeat at Aston Villa two weeks ago.
The Merseyside club's medical staff hoped a short period of rest would be enough for Rodwell to recover, but the injury has now proved worse that was his first diagnosed.
Rodwell was making his first Premier League start of the season against Villa but is now likely to be out of action until the New Year.
Meanwhile, Joseph Yobo has revealed that fears over his place in the Nigeria squad prompted him to seek a move away from Goodison Park.
Yobo joined Turkish side Fenerbahce on a season-long loan last week after falling down the pecking order in recent months.
"During that period, I was under intense pressure," he explained."But now, I am very much relieved and I can now give my 100 per cent to the game.
"It was not easy for me, but I thank God that all is over.
"I have said it time and time again, my national assignment remains paramount to me whenever I'm going into any contract."