The United boss admits he sometimes feels guilty about leaving Evans out of games because he has been so impressive.
The Northern Irishman is still learning his trade at United but has made five appearances already this season. And if it weren't for the form of Rio Ferdinand and Nemanja Vidic, he would have featured even more.
Ferguson said: "Jonny’s been fantastic and it’s very difficult for me at the moment. I said to him last week that I don’t know if I’m doing the right thing sometimes in leaving him out; because his performance level is so high, I feel like I’m being unfair to him.
"I think the only thing that justifies me leaving him out is the performance levels of my other centre-backs, and their experience. Jonny is still young and he’s got a great future here."
While he has difficulty picking his best XI, Ferguson knows that the large pool of talent he has at his disposal is a good way of making sure all his players are on their toes. And he shares Sir Matt Busby's philosophy that if you’re good enough, you’re old enough.
"The great thing about young players in particular is that they might come back after one summer and be a different player, with a different physique, and they tell you by their performance that it’s time for them to go in [the side]," said the Reds boss. "It’s happened at this club countless times.
"I’d say it is a great worry for any experienced player, that one of their own from the academy or reserves is going to take their place."