Lambert is obviously more concerned about Delph's club than his country but suggested full international honours are not beyond the midfielder.
Asked about Delph's prospects of forcing his way into Roy Hodgson's Three Lions squad, Lambert replied: "I'll let England worry about England, my job is to worry about Fabian and Aston Villa, but the way he's playing you just don't know.
"I'm pretty sure there's more to come from him. The way he has started the season is great. If we keep him fit and healthy, the way he is playing, it's up to himself how far he goes.
"It won't be for a lack of trying because he has got a great attitude."
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