The Red Devils skipper is banned for tomorrow night's game at West Bromwich Albion, and the following match against Chelsea, after picking up a red card during their 2-1 victory over West Ham United before the international break.
When asked by The Mirror whether Rooney would regain his spot in the side for the Manchester derby on November 2, Van Gaal said that "every player" must prove their worth in training.
He said: "Nobody is walking back in my team, believe me. You have to earn it on the training ground, but every player here already knows that.
"I have always said that just because players have the best name, it doesn't mean that they are the best for the team.
"I am always looking for a constant level of performance – from the team and from individual players."