A £10m fee is believed to have been agreed for the Brazilian. The 26 year old only joined the Gunners two and a half years ago for £13.5million and it seems Arsene Wenger is prepared to make a loss on the centre back.
Gabriel is believed to have found it difficult to learn the English language and despite being at the club since 2015, he has made little progress in communicating beyond the most basic terms.
The sale of the centre half will come as a surprise to many Arsenal fans who would have thought that the Brazilian would be a vital member of the squad, with Wenger opting for a three man back line this season.
The Frenchman is reportedly happy enough with the players at his disposal to allow the defender to make the switch back to Spain. Gabriel played for Villarreal for two and half seasons before making the move to London, and Valencia boss Marcelino has already publicly stated he wants to sign the centre back due to his experience of La Liga.