Well, he does know basketball.
JohnLucus, one of the quickest point guards in the NBA back when, was always working with HenryHines to refine his movement for pro tennis. John could change direction like Isiah or Kevin the Mayor of Sacramento, but was clumsy moving when he began his second tennis career. He'd gotten used to running and moving for basketball, where the court is much bigger, and pure speed is a necessity.
Not so in tennis. You only cover your half of the court, and not nearly the whole half.
He worked on moving 3', 5', 7', and 9', and back, in HITTING POSITION. He watched JimmyConnors run around bent over with 2 hands on the racket, and he worked hard and endlessly.
I think he ended up top 75 in Men's pro, but was always working on his movement.