McFadden made just three substitute appearances for Sunderland before his short-term contract expired last month.
And with Motherwell prepared to offer the Scottish international a star role, Sunderland never reached the stage where the former Everton forward was handed a new deal.
Martin O’Neill: “The lad needs to play some competitive games, and I couldn’t guarantee that here, although I was hoping we might have resolved something.
“We never got round to offering him anything. His contract ran out here just before the transfer deadline.
“I was sitting down with James, and I had a couple of thoughts of what I could do with him, really wanting him to try to get some football, as it was difficult to get him in here.”