Pogba sparked fresh uncertainty over his future on Sunday.
He told reporters in Tokyo: "I am thinking of this: To have a new challenge somewhere else. After this season and everything that happened this season, with my season being my best season as well... I think for me it could be a good time to have a new challenge."
Pogba still has two years remaining on his current United contract with the option of an additional year which can be extended by the club, so there is no pressure for him to be sold.
Recent speculation has linked the 26-year-old with a move to Real Madrid, and reappointed Real coach Zinedine Zidane has already reiterated his desire to work with the United midfielder one day.