Moises Caicedo missed training on Monday and sources close to the player said he is frustrated over Brighton’s stance around a potential move to Chelsea.
Brighton still do not expect anyone to reach their valuation for Caicedo and insists the situation has not changed.
Chelsea have had a succession of bids for the Ecuador midfielder rejected.
It is not clear whether 21-year-old Caicedo will return to the club’s Lancing training ground on Tuesday.
The Seagulls are continuing preparations for Saturday’s Premier League opener with Luton Town at the Amex Stadium at 15:00 BST.
In January, Caicedo made a public request to be allowed to leave for Arsenal. This was rejected and he subsequently signed a new contract that does not expire until 2027.
Brighton believed Caicedo would continue to behave professionally throughout the current transfer window. Now their position faces being tested.