The 22-year-old winger from Belgium played 63 games for the red devils scoring only 5 goals in the process.
Januzaj failed to impress manager Jose Mourinho after an unsuccessful loan spell at Sunderland last season and as a result, has been told that he is not in the managers plans for the upcoming season.
Januzaj joined Utd from Anderlecht in 2011 at the age of 16 and finally broke into the Utd first team in the 2013/14 season under David Moyes ill-fated stint at the club.
It is disappointing to see how a player once praised to become the next Ryan Giggs has diminished so quickly. But maybe a spell at Sociedad and a fresh start for a player who at 22 is still relatively young, may help Januzaj to kick-start his career and re-light the fire that made Januzaj one of the hottest young prospects in world football.