The club have completed the signing of Brighton & Hove Albion central defender Matt Clarke.
The 25-year-old completed the formalities of his move late Wednesday evening and has signed a three-year contract with a further year's option.
Chris Wilder had earmarked a left-sided central defender as a priority during the transfer window and Clarke arrives with all the credentials.
With almost 300 career appearances to his name, the player brings plenty of experience to the squad.
The player, who joined Brighton for over £3m from Portsmouth in the summer of 2019, spent two seasons on loan with Derby County where he was a virtual ever-present, and he made 33 appearances on loan at West Brom last season.