All I have left is golf

Two guys, one tall and one short, grabbed each others arms with warm hand shakes at Panera's last Friday. Apparently, they were both former athletes, one basketball, the other baseball. Probably not pros, but maybe college. Probably late 50s. They started talking about knee replacements. The shorter of the two had already had two knee replacements, the tall guy said he was afraid it would be soon for him.

The shorter guy said, "All I have left is golf."