The former Gunners midfielder is set to spend pre-season with his former club, with a view to earning a permanent contract
Santi Cazorla has returned to Villarreal as he continues his rehabilitation from an Achilles injury.
The midfielder was released by Arsenal at the end of the 2017-18 season, and has not played a competitive game since October 2016.
Arsenal decided against offering the midfielder a new deal, due to his fitness issues, having been forced to endure 11 operations on his Achilles.
The 33-year-old's injury was so horrific he nearly lost his foot, but he did return to first-team training in the latter stages of the campaign.