Juanfran was replaced during the first half of Atletico Madrid's 1-0 win over Rayo Vallecano and has suffered a hamstring injury.
Following Gabi's departure, Atletico Madrid have confirmed the club's four new captains, including France star Antoine Griezmann.
Diego Simeone has been dealt a blow for big upcoming matches against Bayer Leverkusen and Barcelona with Juanfran straining his hamstring.
Juanfran could miss Atletico Madrid's games against Bayer Leverkusen and Barcelona after the club confirmed his hamstring strain.
With Yannick Carrasco sustaining an Achilles injury, Juanfran will start in midfield when Atletico Madrid take on Las Palmas.