The Dutch international, who joined from PSV Eindhoven in June last year, also endured a difficult debut season under former boss Louis van Gaal, scoring twice in 29 league appearances, 13 of which came as a substitute.
"I am the same person and I know what I want. A supporting role is not for me," Memphis, who scored 22 league goals to fire PSV to the Dutch championship in the 2014-15 season, told Dutch newspaper Metro Nieuws.
"I'm not a player who is happy with the fact that he is under contract with Manchester United. This is my dream club, but I want to play."
Memphis said United had made progress following Mourinho's arrival in May, adding that the former Chelsea boss has expressed his faith in his abilities.
"The training sessions are going well, I'm sharp and fit, but that applies to everyone. The level has become higher. Jose Mourinho is a top coach," he added.
United, sixth in the league after seven games, next travel to Liverpool on Oct. 17.
(Reporting by Ian Rodricks in Bengaluru; Editing by Peter Rutherford)
