Ghana captain Michael Essien has been taken to hospital after suffering a suspected knee injury in training at the African Nations Cup finals.
The Chelsea star, who was prevented from starting Friday's 3-1 defeat against Ivory Coast by a hamstring problem, hobbled off the team bus following a training session on Sunday and was sent for medical tests.
Ghana coach Milovan Rajevac told BBC Sport: "I don't know the extent of the injury but we will find out later."
Essien, who played 45 minutes as a replacement for Mousse Narry against Ivory Coast, started training but pulled up during the session with a problem in his right knee and is a serious doubt for Ghana's must-win clash with Burkina Faso on Tuesday.
Following Togo's withdrawal from the African Nations Cup, Group B was reduced to three teams and if Ghana fail to beat the Burkina Faso the Black Stars will go out.