He believes Celtic deserve huge credit for developing him into a top-class keeper.
His only fear is that his protege could be forgotten about down south if he stays at Parkhead long-term.
He told the Scottish Sun: "I have no doubt whatsoever Fraser will go on to play for England, but sometimes I think that when you go up to Scotland you can be forgotten.
"Celtic have been fantastic for him. He's had to deal with the massive pressure of Old Firm games and has handled those occasions well. The experience will stand him in good stead for the future.
"Celtic have brought him along nice and slowly because he is still learning the game.
"But if Fraser ends up playing for England it would not shock me in the slightest.
"He won't be at his best until he is approaching 30 and will do well into his late 30s because he was a late starter."