James McFadden is yet to hold talks with Sunderland over a potential short-term deal as the club look to further explore potential deals for free agents.
• McFadden on trial at Sunderland
McFadden, 29, has spent the week on Wearside after being released by Everton towards the end of last season. Another free agent, Nigerian defender Rabiu Afolabi, has also spent time with the club after being released by Monaco.
Manager Martin O'Neill confirmed that due to Sunderland's small squad it was worth assessing McFadden, but said no promises had been made.
"He's been here for a few days," O'Neill said. "He has no club, is out of contract and he's been training for some time with Motherwell just to get himself fit.
"We'll see. There's been no promises made on either side. After a day or two working with me, he may not fancy it! He's a very decent footballer, but he was allowed to leave Everton. They must have felt they had enough in those positions.
"We've perhaps got a smaller squad so he's definitely worth looking at."
Despite the transfer window being closed, Sunderland are still able to add free agents to their squad, having registered only 21 of the 25 players allowed.