Joe Riley has returned to Manchester United for assessment after dislocating his shoulder in training with loan club Sheffield United.
The defender, who joined the League One leaders on loan for the rest of the season in January, suffered the injury on Tuesday and is now back with the Reds for further investigation.
The 20-year-old had made two appearances for the Bramall Lane outfit, coming off the bench for the final minute of a 1-0 win at Peterborough United and playing the full 90 minutes of a 0-0 draw with Bristol Rovers.
Riley had previously impressed for our Reserves earlier this term, mainly as an attacking left-back, having made two appearances for the first team under Louis van Gaal in 2015/16.