HITC Sport understands Brentford have bid for the League One defender.
Brentford have made a move for highly-rated Gillingham defender John Egan, HITC Sport understands from sources close to the club.
Brentford are in the market for a new defender after agreeing to sell James Tarkowski to Burnley with the player undergoing a medical at Turf Moor.
Egan has caught the eye at Gillingham this season and has been instrumental in their push for promotion from League One.
The former Republic of Ireland Under-21 international was signed by Sunderland as a youngster, but after five years at the Stadium of Light he never made a first-team appearance for the club.
Egan saw his progress at Sunderland interrupted by a series of injuries during his time on Wearside and he was released in the summer of 2014.
Gillingham moved to snap up Egan and the Cork man has been a revelation for the Gills making over 70 appearances during his first 18 months at Priestfield and chipping in with eight goals.
Gillingham are reluctant to lose Egan as they look to keep hold of their best players to maintain their bid for promotion to the Championship.