Reading defender Liam Moore has handed in a transfer request, according to Sky sources.
The former Leicester player, who arrived at the Madejski Stadium in 2016, has been the subject of bids from Brighton this summer.
Last month, Sky Sports News reported that Brighton made a third bid for Moore, believed to involve an increased up-front payment of £8m, with a series of add-on payments.
The 25-year-old has three years left to run of his current deal at Reading.
He joined the Royals from Leicester in the summer of 2016 and was part of the side who lost the Championship play-off final against Huddersfield at the end of that season.
The 2017-18 campaign was less successful for Reading, as they only avoided relegation on the final day, but Moore managed to play in every minute of every league game.