Arsenal have announced that midfielder Santi Cazorla is leaving the club and will not be handed a new contract.
Cazorla is at the end of his current deal after being given a one-year extension last summer by Arsene Wenger despite a long-term Achilles injury that ruled him out for the entire campaign.
"I'm very sad to be leaving after so many great times," Cazorla said in a video-recorded message. "I have loved my time with the club."
Cazorla recently returned to full training after undergoing 10 operations on his injury and will join his former club Villarreal for their preseason preparations.
"Santi Cazorla is very loved at Villarreal," Villarreal president Fernando Roig told Levante. "He is loved and he is in a very special situation because of the injury which he is recovering from. Santi has the doors open for everything we can help him with. We shall see what happens in the future."
Cazorla joined Arsenal from Malaga in 2012 for £17 million and emerged as one of their most influential players on the pitch in his role as a deeper-lying playmaker.
"Santi is always one of my favourite players to watch. His natural ability with both feet, his speed of thought and movement were central to our best performances in recent years," Arsenal chief executive Ivan Gazidis said in a statement.
"He plays with a joy and freedom which is very rare. We wish him well for the future and thank him for his important contribution to our club."
Cazorla scored 29 goals in 180 appearances, including a free kick in the 2014 FA Cup final that kick-started the Gunners' comeback from a 2-0 deficit against Hull.
However, he hasn't played since injuring his right Achilles tendon in October 2016, which led to a series of complications that involved multiple surgeries and a skin graft from his arm.
Arsenal struggled mightily to make up for his absence, with their lack of a dominant central midfielder one of the reasons for two consecutive Premier League finishes outside the top four.