Louis van Gaal isn't sure if Wayne Rooney can be Manchester United's No. 10 in his new system.

Van Gaal had planned to use Rooney as his main striker this season, but new signing Anthony Martial has scored four goals in as many games to stake his case to lead the line.

"I have to wait and see if he can play as a second striker in this system, which we now play," said Van Gaal.

"I think that Wayne can play a lot of positions. He has shown that last season. I want to play with a first striker and a second striker and maybe they are a very good duo together. We shall wait and see."

Van Gaal still intends to deploy Rooney as a No. 9 when his sidekick in attack is Marouane Fellaini, rather than Martial, explaining the need for pace in attack is why he has not allowed James Wilson to go out on loan.