Coly is currently on-loan at Birmingham City but has failed to make an impact with the Midlands side since joining them from Lens in December last year and Blues boss Steve Bruce looks unlikely to offer him a permanent deal in the summer.
Senegal international linked
Black Cats boss Mick McCarthy was said to have been impressed with Coly in the recent Reserves clash between the two side and has enquired as to the availability of the Senegal full-back.
Birmingham first team coach Mark Bowen said: "My understanding is that Sunderland have shown an interest in him. He has played well in the last couple of reserve team games.
Birmingham first team coach Mark Bowen said: "My understanding is that Sunderland have shown an interest in him. He has played well in the last couple of reserve team games.
"Obviously he has been seen by quite a few clubs in recent weeks and I have no idea what is going to happen."