SANTA CLARA, Calif. — His mind is certainly sharp, but Peyton Manning’s list of ailments over an 18-year NFL career includes four neck surgeries plus rib, ankle and foot injuries. But while the rest of the world remains focused on his age, the 39-year-old Broncos quarterback would rather not dwell on his physical limitations.

“I think it is important to use all of your experience to your advantage,” Manning said Wednesday, explaining how his game has changed over time. “Certainly, I have some physical differences with the years I have played, certainly since my major [neck] injury four years ago. I think it is about learning to adjust, learning to adapt.”

And make no mistake — Manning knows he’s still got it.

“Using the baseball analogy, the guy that used to throw 95-plus as he gets older, maybe he can’t still throw that same fastball, but he can work the corners of the plate and still strike a guy out,’’ he said. “I feel like I can still move the chains. Maybe in different ways. That is being flexible and being able to adjust. I think that has served me well.”

So which is better — his arm or his mind?

“I feel like I have worked hard at both. I think both of them have played a big role in my career as a quarterback,’’ he said. “I have studied the game. As a quarterback, I think you have to. You have to be a student of the game and then physically you have to keep yourself in top shape to try to stay healthy. Try to keep improving, and I have really worked on both of those things throughout all the years that I have played.”

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But Father Time is undefeated, and Manning knows this. A

lthough he has refused to put an official end date on his Hall of Fame career, he acknowledged his body is breaking down more than he’d like to admit. Asked about the lasting physical effects of playing football, he said he’s already been warned that he’ll need hip replacement surgery in the not so distant future.

“When you have injuries, when you have surgeries, the doctor sometimes will mention to you —whether you ask him or not — ‘Hey, you are probably heading for a hip replacement at a certain time in your life,’ ” Manning said, with a smile.

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“I said, ‘Doc, I didn’t ask you if I was going to have a hip replacement. I didn’t need to know that right here at age 37, but thanks for sharing. I look forward to that day when I am 52 and have a hip replacement.’ ’’

He also knows there’s no guarantee he won’t need another operation on his neck.

“Am I going to have some potential neck procedures down the road? I don’t know the answer to that,’’ he said. “The hip part was true. I can’t remember which doctor told me that. I have seen a lot of doctors. He was nice enough to share that information with me.

“I feel like I do a lot of things to try to ‘prehab,’ if you will. Preventive type of stretching. I wear a posture shirt and different things like that. As those things come along later in life for me, I will try to handle them and try to have a good plan. I feel pretty good as we speak and I am fortunate for that.”