Not since the early days of Sir Bobby Robson's reign has Harper ousted Given from the number one spot for an extended period, although recent injuries have presented him with a succession of opportunities.
Keegan has been hugely impressed with both his form and his attitude and admits the club's strength in that department could give him a genuine, if pleasant, headache.
He said: "Steve has not given me anything to think about that I have not thought about before. I have always said we have got two great keepers here.
"There's no doubt about it, Shay's absolutely top notch, and Stevie is right there with him, and he's proved it in these games.
"We have protected him well, but whenever he has had to do anything, he's done it well.
"That's not a surprise - he has done it before. It's well known around the leagues that, in the Premier, we have probably got the two best keepers.
"Some have probably got a number one and a number two - we have always had two that are very close.
"Shay has had the nod for a long time, but through circumstances, Stevie has got the opportunity.
"He's been very loyal. He cares, don't get me wrong, he doesn't like not being in the team.
"But he knows how to handle not being in the team - and he knows how to handle being in it."