According to Foot Mercato, the Spanish topflight are keen to secure a deal for the centre-back, who has struggled to establish himself since moving to Stamford Bridge.
Al-Hilal are also interested and have reportedly presented their plans to Sarr. The opportunity to play alongside compatriot Kalidou Koulibaly could prove influential in his decision.
Sarr joined Chelsea from sister club Strasbourg last winter after becoming a regular in Ligue 1.
However, he has made only seven appearances for the Blues, finding opportunities limited in England.
Despite his lack of game time, Sarr was selected by Senegal coach Pape Thiaw for the World Cup but did not feature.
