Manchester United midfielder, Christian Eriksen, suffered an ankle injury during their 3-0 win over Reading in the FA Cup fourth round on Saturday.
His injury was confirmed by manager Erik ten Hag after the game.
Ten Hag, who faces a hectic fixture schedule in February with eight matches, says it is “difficult” to give a diagnosis.
However, Eriksen will be assessed over the next 24 hours.
Casemiro scored twice in the second half to send the Red Devils on their way into the next round.
Fellow Brazilian Fred rounded off scoring for United, who will now go into Monday’s draws.