The Atletico Madrid goalkeeper had been on trial with the Latics prior to the move and the club is expected to make an official announcement on the transfer today.
Joel has been signed to add competition for the goalkeeping spotwith Oman international Ali Al Habsi.
The young Spanish goalkeeper spent the tail end of last season on loan with Rayo Vallecano and given the recent injury to Mike Pollitt he will become immediate understudy to Al Habsi and isexpected to challenge hard for the number one spot.