The defender has become a virtual ever-present this season.
Pardew said: "Mike is under-appreciated as well. He has gained experience and confidence from his performances. You have to say he is a Premier League centre-half now when before he was still earning that right.
"I think his best years are ahead of them. Centre-halves get better from 28, 29 onwards. They know when to challenge, when to back off, or step in front of the striker, read a pass.
"Young centre-halves always make errors because they get that wrong. Mike has got a lot better at decision making."