Jesse Lingard has had the one-year option on his Manchester United contract triggered.
Lingard's contract now runs until the summer of 2022.
Earlier this month Sky Sports News reported that Lingard's representatives are exploring loan options for the United midfielder in January, with Real Sociedad one of the clubs they have held initial talks with.
Lingard has not featured in the Premier League or Champions League this season despite making the squad for both competitions.