It has been a tough start at the new office for Mr.Van Gaal, as his side have just managed to win one out of the six games played. The recent loss at the hands of Leicester, pointed at the team's defensive frailties as United lead 3-1 to lose the game 5-3. Manchester United have suffered a large number injuries at an alarming since Van Gaal took over.
Jonny Evans bruised his ankle against Leicester and Tyler Blackett was yellow carded twice as he was sent against Leicester.
Chris Smalling injured himself in training on Wednesday and will not be fit enough to feature against the Hammers, while Phil Jones remains sidelined with a hamstring problem.
Means Van Gaal could be forced to deploy Rojo, who has been used at left-back this season, and either Daley Blind or Darren Fletcher, both midfielders, at centre-back against Sam Allardyce's side.
"All the three right-sided centre-halves are out. I don't know how long they will be out for," van Gaal told reporters on Thursday.
"Evans is a very difficult one. His bone is bruised a lot and we have to wait and see, to evaluate it."
Van Gaal on giving the academy boys a chance: "I have to admit that I'm never in this situation before so that's strange," he said.
"For me it's difficult to understand because we are evaluating what we can do in a different way but you have to train on a certain level because otherwise you can't play a game.
"I've already said I will adapt to a certain level but I cannot train lower because then you can't perform in the right way.
"We have a lot of injuries, nine injuries now, and Blackett suspended, so that means that 10 are off so I have to go to the youth team to pick players.
"The younger players can pick their chances now and that's also the policy of this club."