Santos has found himself on the fringes of the Arsenal first team since joining in the summer of 2011, and spent the second half of last season on loan with Gremio.
The 30-year-old returned to the Emirates for the start of pre-season training, despite the Gunners desperately seeking a buyer in hope of getting the full back off the wage bill.
Manager Arsene Wenger was becoming concerned with being unable to shift the Brazilian, with the club needing to shift dead wood in order to bring in new signings and free up more money for wages.
Therefore the news Santos has agreed to cancel his current deal and return to Brazil will come as a relief to Wenger, and the club’s supporters.
Gunners fans took a strong dislike to the full back, following a series of poor displays, and a bizarre incident which saw the player swap shirts with Manchester United forward and Arsenal enemy Robin van Persie at half time of Arsenal’s 2-1 defeat at Old Trafford last season.
The Brazilian ended his Arsenal career with 25 league appearances and two goals, the most important coming in the 5-3 victory over Chelsea at Stamford Bridge during the 2011/2012 season.