Sheffield United manager Chris Wilder has revealed that full-back Joe Riley has returned to parent club Manchester United after dislocating his shoulder during "a bit of a freak accident in training".
Riley, 20, made his debut for Sheffield United in their goalless draw with Bristol Rovers last weekend and had been due to spend the remainder of the season with the League One side.
However, the youngster is now back at Man United and will undergo a scan before the end of the week to determine whether he will play again this season.
"It's was a bit of a freak accident in training. It was something an nothing. He stumbled and fell and dislocated his shoulder. It's desperate bad luck for Joe and for us," Wilder told reporters.
"He played last week at Bristol Rovers and can be very pleased with his debut. Those scan results will see if he's back with us or that's his season done."
Riley made his Man United debut against Shrewsbury Town in the FA Cup last season, before making his first start for the Red Devils in the Europa League against FC Midtjylland.