Brentford have accepted a £9m bid from Championship rivals Bristol City for striker Andre Gray.
The 24-year-old, who had been a target for Hull City, is believed to be discussing personal terms with Steve Cotterill's side.
Should the deal go through, Luton Town will receive a seven-figure sum after agreeing a sell-on clause when Gray moved to Griffin Park last summer.
The striker scored in Brentford's 4-2 victory over the Robins on Saturday.
The former Shrewsbury and Hinckley United forward scored 18 goals last term as Brentford reached the Championship play-offs.
Bristol City, who won the League One title and Johnstone's Paint Trophy in 2014-15, have lost both league games so far this season and were knocked out of the League Cup by League Two Luton.
They had been pursuing a deal for Crystal Palace striker Dwight Gayle, but the player opted against moving to Ashton Gate.