Sky Sports understands former Oldham winger Lee Croft is training with Millwall as he seeks to land a free transfer.
The 27-year-old was voted Player of the Year at Boundary Park by Latics fans last term, but chose to reject the club's offer of a new contract in May.
Croft, who has also been linked with Doncaster in recent weeks, is known to be a target for new Millwall boss Steve Lomas.
Lomas welcomed his players back for pre-season fitness tests last Monday and will now take them to Warwick for a more intensive programme ahead of their first friendly at Crawley on July 13.
Former Manchester City and Norwich man Croft played in all but one of Oldham's League One fixtures in 2012/13 and was one of the stars of their memorable FA Cup run.