The 34 year old signed for the Blades last summer after spending three months on loan from Preston North End and played in the Play-Off Final in Cardiff which was lost 3-0 against Wolves.
Mark Rankine:Now at Tranmere Rovers.
In all he made 15 appearances and 10 substitute apps without scoring a goal. The slow but strong Centre-Midfielder was one of seven squad members released by Neil Warnock this summer as he attempts to bring in stronger players.
He can now begin life in Division Two with Tranmere Rovers.