Sunderland striker Roy O'Donovan has undergone surgery to remove his appendix, and faces an undetermined spell on the sidelines.

The young Irishman is currently on-loan at Blackpool and complained of feeling unwell before his side's game at Sheffield United on Tuesday, a match they drew 2-2.

The 23-year-old was taken to a local hospital, and the club have since confirmed he has had an operation.