Despite only being in the second week of June, Nigel Clough has secured his seventh signing of the summer, with midfielder James Wallace joining from Tranmere Rovers for an undisclosed fee from the 1st July.
The 22-year-old, who has skippered the Prenton Park outfit in recent seasons, arrives in South Yorkshire, penning a three-year contract.
Wallace started his career in Everton's Academy system at the age of 13 before progressing to play for the Toffees reserve team on a regular basis.
The midfielder made his senior debut at Goodison Park in August 2009, before furthering his development with loan spells at Bury, Stockport, Shrewsbury, Stevenage and latterly with Tranmere.
In January 2012, Wallace, an England U19 and U20 international, moved to the Wirral on a permanent basis despite reported interest from a host of Championship Clubs.
Last season he made 19 appearances, before injury curtailed his season in late March.
The addition of Wallace comes after Ben Davies and Chris Porter signed new one-year deals with the Blades on Monday.
Marc McNulty, Jamal Campbell-Ryce, Chris Basham and Andy Butler complete the list of Clough's additions during the close season to date.
On his latest recruit, the Blades boss remarked: "James is another good young midfielder to add to our ranks.
"He's had a couple of injury problems in the last twelve months but he was the driving force behind Tranmere's fine start a couple of seasons ago.
"James is one of the best midfielders in the league. We are delighted to get him; it adds extra competition for places."