I never saw Koufax pitch but I did play a game of pickup basketball against him.
After he retired he moved to Maine for a short time & lived about 10 miles from my home - but way out in the boonies!. The guys I played golf with also played pickup basketball on Sunday mornings and I was invited to come along one Sunday. (Amazing, because I may be the worst basketball player ever to walk onto a court. I'm completely landlocked...but that's another story). Unbeknown to me Koufax was also one of the Sunday Morning basketball guys.
I only met him that once but I'd say he's a great guy but not a great basketball player. And his left arm was a LOT bigger than his right.
-one of my few claims to fame.
And BTW, he was only here for a few years. His wife hated being that far out in the country so they left.