Speaking with the Guardian, Van Gaal says United are to tap into their former players' pool.
"As a good player, you're not a good manager or you're not a good technical director," he said of Ferdinand.
"It's more or less what is happening now with [Ole Gunnar] Solskjaer, ex-players, old boys' network.
"It's not always a good choice. It can be but it's not always a good choice."
He added: "Because Manchester United is one of the biggest clubs in the world that needs a manager with experience.
"Not a manager who has trained at one or two teams and on a lower level."