The Belgian has struggled to find his best form since joining the club from Everton last summer, but he has dismissed suggestions that Van Gaal wanted him to leave Old Trafford when the Dutchman replaced David Moyes.
"I talked to Van Gaal and he has never said that I had to leave," Fellaini told members of the media. "He said I had a lot of competition, but that I got the chance to prove it.
"I have known difficult moments last season, but there is a stronger player afterwards. I have confidence in myself and in my game again.
"I played a good World Cup and also during the preparation, I was good. It is unfortunate that this injury is for now just a spanner in the works, but at the end of the month I will be back."
Fellaini has been out of action for a month due to an ankle injury.