Albion could end up pocketing £10 million from the sale of Leo Ulloa to Leicester City.
The Seagulls will receive an £8 million downpayment for Ulloa’s move to the Foxes.
The bounty will potentially rise eventually to eight figures, depending on how many appearances the Argentinian makes and how successful he is with the Premier League newcomers.
Ulloa's switch to the East Midlands will be officially confirmed on Monday.
He said goodbye to his Albion team-mates and staff on Thursday night, when the Seagulls were beaten 3-1 by Real Betis in a friendly in Pinatar, before flying to another part of Spain to spend the weekend with family members.
Ulloa’s representatives, meanwhile, went to Leicester’s training camp in Austria for discussions on personal terms after the clubs had finally agreed a fee.
The loose ends will be tied up for Albion by chief executive Paul Barber, who is responsible for dealing with outgoing transfers.
- Keeper congratulates his Albion colleagues - and could still make it a treble
- Albion's loss could be a blessing in disguise says Sidwell
- Promotion celebrations may have affected Albion admits boss
- Sussex ace Konta left in tears after being abused by Romania captain Nastase
- Sussex thrashed inside two days by Nottinghamshire