Manchester United manager Louis van Gaal has reiterated that Radamel Falcao will not be offered a place within the Red Devils' starting line-up before he can prove his fitness.The striker picked up an injury in October which ruled him out for one month, and has since made just two appearances from the bench against Hull City and Stoke City.And the Dutchman has refused to steer from his philosophy of his players regaining match fitness in the reserve squad before being considered for a Premier League starting spot.When asked whether Falcao's omissions have been fitness-related, he told reporters: "Yes, match fitness. He has trained now maybe two days after the match [with Hull]. So we had the match against Stoke on Tuesday when he played for 15 minutes. "Then we had the training sessions after Tuesday. And before Tuesday I didn't train – I trained the box exercise. You know the box exercise? Yeah? It is not a training session."We had to play again within two days after the Hull City game, then I have to recover the players. Then I cannot train him. After Tuesday I can train him. And we have trained very well on Wednesday. "Then Thursday they are off. I can say to him to train but, no, we have trained before that. Then on Friday we had a training session. So he has trained in two training sessions. But a bigger contribution is to play in the second team for 45 or 60 minutes or even 90 minutes – what Jonny Evans has done already."But I cannot do that because I need him because [Wayne] Rooney was injured [for Stoke]. James Wilson was injured also [for Hull]. I have to adapt to the needs of the selection. Then I selected him in spite of the fact he can only play 20 minutes at that level because the rhythm of the game in the Premier League is the highest."Since joining on loan from Monaco, the striker has bagged just one goal for the Old Trafford outfit and when asked whether he could start against Southampton on Monday, Van Gaal dismissed his chances."I'm not interested. He has to follow my philosophy. Do you understand that? Yeah, I'm here because of that", he said.