Walker claims he would like to end his career back at his beloved Blades having spent 12 years with his boyhood side before leaving to join Tottenham in 2009.
“Kyle's a Sheffield boy," said the Blades manager. “I tried to tap him up when we played City but he said he's got a another couple of years playing there.
“He's one I would take and I think the world of him. I'm sure we'll be able to find a role for him when he decides to leave Manchester.
"He's a top player and he's already said he wants to finish what has been a brilliant career back at Sheffield United. Don't count against it.
“He's got my number and he knows he can phone me anytime.
“He's still a top performer in the best league in the world. He's welcome back here anytime."