Wigan boss Paul Jewell is currently waiting to hear if he has been successful in a move for Liverpool goalkeeper Chris Kirkland and may let Filan go if he lands the former Coventry man.
36-year-old former Australian international Filan has been with Wigan since 2001 and played a number of games for them in the Premiership last season.
He had a short loan spell with Forest earlier in his career but did not make a senior appearance.