The 30-year-old spent a year at Glanford Park, but failed to oust Peter Beagrie from the starting line-up.
He spent the end of the season on loan at Brisbane Road, helping them secure the final automatic promotion spot in League Two, and now looks set to make the move permanent.
Speaking of his time with United, he said: "I've enjoyed my time here and I'd like to think I've played my part.
"I'd like to thank the gaffer for giving me an opportunity, it was getting stale at Scunthorpe and I needed to get out."