Castillejo suffered a bruise to his fibula bone during his side's 1-2 loss on Saturday, reports Efe.
Villarreal's coach Javier Calleja is expected to be able to count on Castillejo in the upcoming match against Alaves on February 10, along with Adrian Marin Gomez, who also returned to group training on Tuesday after being sidelined for three weeks.
Midfielder Roberto Soriano remained unable to exercise due to ongoing knee problems.
Villarreal are currently missing Bruno Soriano, Andres Fernandez, Nicola Sansone and Ruben Semedo because of injuries.
Villarreal hold the fifth position in the La Liga table with 37 points, just two points behind defending champion Real Madrid, while unbeaten Barcelona lead the table with 58 points.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
