The 28-year-old stopper started his career at Real Madrid and was tipped for a big future after starring for the club’s ‘C’ and ‘B’ teams before graduating to the first-team set-up.
However, the form of Los Blancos idol Iker Casillas limited his playing time, and Adan has since left the Bernabeu.
Now at Betis, the stopper seems to have found his feet, and his form has alerted English sides, with reports highlighting Liverpool as an interested party.
Adan has a release clause of around £6.2m in his contract with the Seville-based side, which could make him a viable option to challenge Simon Mignolet next season.
The now Betis star was controversially picked ahead of Casillas during Jose Mourinho’s latter days in charge of Real.