Derby County manager Nigel Clough fears that both Paul Green and Gareth Roberts will miss the Championship run-in with knee injuries.
Midfielder Green and left-back Roberts were both hurt during Saturday's 4-1 defeat against Cardiff City.
Green was replaced before half-time and Roberts was taken off on a stretcher after the break.
Clough said: "We suspect ligament damage. If that is the case, they will be out for the rest of the season."