Perhaps you'd do best to encourage his pursuit of sports as a form of self-fulfillment; encourage the discipline and physical benefits it brings rather than where it might get him if he "makes it big." No sense setting him up for disappointment if he's not one of the VERY tiny percentage who are lucky enough to play sports professionally.

I took up running in my early 30's, and absolutely love my alone time. Nothing better than an hour of chugging along at the end of my day, and it keeps me somewhat fit. Hopefully he can enjoy the same sense of satisfaction and enjoyment pursuing football, and maybe it'll pay for his school to boot!

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1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)