Republic of Ireland defender Clive Clarke is now in a stable condition in hospital after collapsing during Leicester's Carling Cup tie with Nottingham Forest last night.
The 27-year-old was rushed to hospital after losing consciousness in the dressing room at half-time.
The game was abandoned as a result.
Leicester say they do not know what happened, but they have paid tribute to medical staff who revived Clarke at the ground before taking him to hospital.