Fergie has a major selection headache ahead of Sunday's top-of-the-table clash with Chelsea in the Barclays Premier League, after Hernandez scored twice in midweek to stake his claim for a starting place alongside either Wayne Rooney, Robin van Persie of Danny Welbeck.
"It's a good problem to have" said Sir Alex. "I don't always enjoy it [telling players they're not playing] but it has to be done. In fairness to all the players they've accepted it well and adapted to it. I don't have any great problems other than having to tell one or two of them they're not playing.
"Chicha was tremendous the other night. He's a really terrific player and such a dedicated footballer and professional in every training session. He's improving - that's the good thing about him.
"The thing that is making the difference to him is he got a proper rest in the summer. It was exhausting in the way it had been in the previous three years for him. That's helping him."