Matt's Done his shoulder

Done, 27, sustained the injury in a collision during a pre-season friendly win at Matlock on Tuesday night and was later taken to hospital.

Blades boss Nigel Adkins tweeted after the game: "A real shame for Matt Done who will miss the season start after breaking his Collar bone in tonight's 4-1 win at Matlock Town."

Adkins is waiting to learn the full extent of the injury but Done has been ruled out of his side's opening-day Sky Bet League One game at Gillingham on August 8.

Done signed for the Blades for an undisclosed fee from Rochdale at the end of last January's transfer window and scored eight goals in 17 appearances.

He had only been converted to a striker from his previous midfield role at the start of last season and scored 14 goals in 30 games for Dale before moving to Bramall Lane.