Doesn't pretty much every athlete have arthritis in the knees by 30? I know I did, and I sure as heck have fewer miles than any of these guys (since I pretty much hung it up at 23).
So, sure, he's got arthritis. He's also a bit of a [insert favorite euphamism referring to female parts] when it comes to playing with discomfort. Hard to tell with these sort of things whether the larger problem is in his knees or his heart.
I know a guy who takes cortizone shots just to get a good day of skiing in, for pete's sake. I doubt JO loves the game that much.