David Button is set to leave Brentford to join west London rivals Fulham.
The 27-year-old goalkeeper, who first moved to Griffin Park in 2013, had a year left on his contract.
However, the two parties were unable to come close to an agreement and the Bees have elected to let their number one depart for their local rivals.
Brentford already have their new number one in Dan Bentley at the club, after he joined from Southend on a free transfer, while they also have Jack Bonham in place as back-up.
Button will move to Craven Cottage and he is expected to be deemed the club's number one, although Marcus Bettinelli will be trying to oust him.
In pictures: Last time Brentford faced Fulham
The 24-year-old established himself under Kit Symons but a knee injury led to the England U21 international missing the majority of last season.
Fulham struggled last season, finishing 20th and 11 points clear of the relegation zone, 14 points adrift of the Bees, while they also had the third worst defence in the second tier, conceding 79 goals, which was only just less than relegated duo Charlton (80) and Bolton (81).
Button is the third player to leave Griffin Park this summer following Jake Bidwell, who joined fellow west London side QPR, and Jack O'Connell, who moved to Sheffield United, out of the exit door.
The 27-year-old becomes the fifth new face at Craven Cottage, after Floyd Ayite, Sone Aluko, Denis Odoi and Tomas Kalas, while Michael Madl made his loan move permanent.
