Manchester United boss Louis van Gaal says new players will not find it easy to settle down at the club.
The Red Devils signed a number of key players during the summer transfer window and although the manager believes they can easily slot in his formation, they will need time to settle down.
"They [Falcao and Blind] have to perform our philosophy and this is not so easy, as we have seen already," the manager said at the unveiling of Falcao and Blind on Thursday.
"I think the players we have selected can do that better, otherwise we would not have had to sign these players.
"We bought five players, one player is on loan here and maybe we can buy him, that is Falcao.
"We let 14 players go, so fitting these players in is not so difficult when only six come in to replace them.
"We now need youth and youth education, which is a policy of Manchester United. When you don't let players go to other clubs, then you're never allowed to give youth players a chance.
"Because of this policy we can now give youth players a chance but the question is whether they take that chance.
"Of course it is a bit risky but I think it's the only way to do it."
