Sunderland boss Gus Poyet says the club is hoping that Steven Fletcher's season is not yet over.
The Scotland striker injured his ankle in the weekend's 0-0 draw with Crystal Palace but the extent of the problem is not yet known.
The injury is at the same spot where Fletcher underwent surgery last season and if severe enough, would likely rule him out for the remainder of the campaign.
Black Cats manager Poyet will wait for a final verdict before ruling Fletcher out as the Wearside club looks to push out of the Premier League relegation zone.
"We are still assessing. I think next week, we are going to have the final decision on him, but he is not fit for this weekend and we are trying to see what we are going to do," Poyet said of Saturday's trip to Norwich City.
"It was quite swollen, so it's difficult to do all the tests. When you do the MRI tests, there is always some swelling around and it's not very, very clear, so we are trying to be calm and assess it properly next week."
Fletcher has made 13 starts for a total of 20 league appearances this campaign, scoring just three goals.
