Grant Hall has left his new Albion contract unsigned.
Now boss Gus Poyet admits the club have almost certainly seen the last of the young defender.
Hall was offered a three-year deal by the Seagulls after showing promise for the development squad and in limited senior outings last season.
The 20-year-old centre-back, who has been linked with Spurs, now becomes a free agent although Albion are eligible for compensation from the club who sign him as he is under 24.
Asked if Hall could be back, Poyet said: “We know nothing. It doesn’t look at all like it. It would be very strange if he came back now.”
Hall came off the bench in the 3-0 win over ten-man Southampton in January and started home and away against Wrexham in the FA Cup.