The Greek international has headed to Fortuna Dusseldorf.
The Greek international joined Sunderland from Panathinaikos in 2013. The fee was undisclosed, but Sky Sports reported it was in the region of £3 million.
He went on to become yet another Paolo Di Canio flop. He played just six times for the club, scoring one goal, and in fairness was not performing badly for a then teenager signed from another country.
He dropped out of contention completely last season and was loaned back to Panathinaikos for the 2014-15 season.
Recently he has been in reasonably good form for the Sunderland Under-21s and earned a place back among the Sunderland first-team set-up.
However despite his apparently improved standing among the Sunderland squad he has been allowed to leave the club.
Mavrias has joined German second tier side Fortuna Dusseldorf this afternoon, who are involved in something of a surprise relegation fight. The club have the option to sign the player in the summer and it could be he has played his last of very few games for Sunderland.
The decision to loan out Mavrias looks to make sense but once again it sums up the poor business done by Di Canio and his team at Sunderland.
Mavrias, a Greek international, will be hoping to help Fortuna get clear of the relegation places and prove a point or two at Sunderland...
Can't believe Mavrias was never given a proper chance by #safc Always looked decent when given the opportunity! Another waste of money!— Matthew (@MJacko1989) January 27, 2016
Mavrias made only two starts - one in PL - for #safc. Thought he deserved more of a chance than that, to be honest— James Hunter (@JHunterChron) January 27, 2016
Mavrias loan deal includes option to buy. Means Mannone likely be only player left next season of awful summer of '13 under De Fanti #safc— Craig Johns (@craig_johns) January 27, 2016