A report in Marca claims the Spaniard will be sold this summer as he wants first-team football and is game time at Los Rojiblancos will be limited due to Jan Oblak.
It follows on from a report in Diario AS that Portuguese giants Sporting CP are closing in on a deal, which is expected to be confirmed in the coming weeks.
Earlier this week, reports claimed West Ham goalkeeper Roberto Jimenez is on Atleti’s shortlist, with the latest report backing up such a claim.
Olympiakos goalkeeper Jose Sa – formerly of Porto – is said to be another option for replacing Adan, who joined Atleti from Real Betis in the summer of 2017.
Argentine goalkeeper Axel Werner is the other goalkeeper on Atleti’s books, but his future also remains unclear after returning from a loan spell at Atletico San Luis.