Speaking to the Official Club Website, Royle confirmed : "Sheffield United contacted us about Andy earlier in the week but we have not received any follow up to their initial interest at the moment.
"Andy has reached a stage in his career where he needs a new challenge and we are hoping something can be sorted out for him."
Other clubs linked with the third choice Town goalkeeper include Fulham, Reading and Stoke City. Marshall has made 66 appearances for the club since joining Town on a free in July 2001.