The Serbian forward has struggled to make any impact at the Wanda Metropolitano following his arrival in July 2019, with just two substitute league appearances last season.
He has not played a single minute of league action in 2020/21 and Diego Simeone is open to allowing him to leave the club.
As per reports from Diario AS, Saponjic has already arrived in Andalucia for a medical and will join Alvaro Cervera’s team on loan until the end of 2020/21 with a purchase clause included for the summer.
If a deal is completed in time, Saponjic could go straight into the Cadiz matchday squad to face this weekend to face Sevilla.
Simeone is unlikely push for a replacement having already secured a deal to bring in Moussa Dembele on loan from French club Olympique Lyon.