The 26-year-old has been linked with a loan move away from the club in order to save his place in the World Cup squad for next summer.
Fergie said: “Ben is staying here. He’s made a couple of mistakes in games where his performance level has been good.
“The problem is he’s got Edwin van der Sar in front of him.
“Is he England’s best keeper? Yes, without doubt. He’s got the best presence, he’s the quickest and brave.”
He added on wich goalkeeper he feels England boss Fabio Capello should choose: “It depends on the standard he has got to choose from.
“He’s had time to see the qualities of Ben and that assessment will bear fruit in the next few months in who he takes.
“I’m not protecting Ben because he’s my keeper, but I look at the abilities of those that are English.
“I don’t think they’re as good as Ben Foster.”
