Manchester United and AC Milan are both interested in Pervis Estupinan and Brighton are prepared to listen to offers for their Ecuadorian left back.
Estupinan has given three years of excellent service at the Amex Stadium since his arrival for £20million from Villarreal.
At 27, Brighton will not stand in his way if he wants to leave for another challenge and bids close to £40m would tempt them.
Manchester United spent £25m on 20-year-old Patrick Dorgu, a Denmark international, from Lecce in January to operate at left wing back.
They are also keen on Estupinan, who has much more experience and is proven in the Premier League as a solid full back with attacking threat.