The Mali striker was replaced by Simon Davies after 29 minutes of the 1-0 defeat.
Physio Geoff Scott told us afterwards: "Fredi lunged forward for a ball and felt some tightness in his hamstring.
"He tried to play on for about 20 minutes but it was too painful for him. Our initial examination suggests he's got a hamstring strain but we'll check it again tomorrow (Sunday) and take it from there."
Fredi Kanoute limped out of Saturday's clash against United with a hamstring problem.