Landon Donovan may already have played his last game for Everton according to manager David Moyes.
The American's loan spell with the Toffees was due to come to an end after Saturday's FA Cup clash with Blackpool.
But the 29-year-old could now miss the game as he is suffering with flu ahead of his return to the Los Angeles Galaxy.
Moyes said: "Landon's been great all round, he's contributed in every area.
"On the pitch and off the pitch he's fitted in really well, he's been a great ambassador for American football players and I'm sure everyone will look at him and say he's been excellent in the time he's been here.
"Unfortunately, he's got a bit of flu and he may miss the game. I'm not sure yet."
New signing Nikica Jelavic will also miss the game as he is still suffering from athletic pubalgia, an inflammation of the pubic bone.
Moyes added: "Nikica has got pubalgia. Most people who are in sport will know about it and it's an injury which, depending how severe it is, can keep you out for a short time or it can keep you out for a longer period.
"So it's something we're monitoring."