As reported by 'France Football', the two clubs have reached an agreement by which Adnan Januzaj will join Real Sociedad for a fee of around 11 million euros.
Real Sociedad manager Eusebio has authorised the move as he believes the former United promise to be the missing piece to strengthen the flanks, alongside Mikel Oyarzabal.
The Belgian winger ended his contract in 2018, but after loan spells at Dortmund and Sunderland, the player is expected to reach and agreement with Real Sociedad.
Manchester United would include a re-purchase clause which they could bring into effect over the next three seasons.