Chelsea striker Daniel Sturridge has until Friday to prove his fitness ahead of Team GB's Olympic campaign.
The Chelsea forward has been missing from Stuart Pearce's preparations for the Games due to suffering from meningitis.
However, Sturridge is now back in the fold following his recovery from the illness, and has until the end of the week to prove that he is match fit.
"We would have to know, probably, by Friday evening whether we feel as though he is going to be physically up to taking on a tournament of this magnitude," said Pearce.
"And then at that stage, if we do not, we have got to apply to FIFA in regard to getting a stand-by player to take his place.
"We have got our fingers crossed. Knowing the attitude of the lad, I'm hopeful [he will be fit]."
Team GB face Brazil in a pre-tournament friendly on Friday in Middlesbrough.
