"It's a massive loss for England," he said. "John Terry is a player of unbelievable talent and he has helped his country so much and is also a stalwart for Chelsea.
"It's difficult for a player like him to take a decision like this. But from the perspective of the England squad... it leaves manager Roy Hodgson in a difficult position.
"I'm not taking anything away from the other England centre backs but John Terry is a player of great talent."
The former Chelsea manager added that he will continue to "back [Terry] 100%", but understands the "frustration" of both parties.