LONDON—Gather around, everybody. Old Man Bryant has something he wants to say. He may want to tell you about Anthony Davis's tenuous position as the youngest player on the U.S. men's basketball team: "If he doesn't listen, we're going to shave his unibrow." Or Russell Westbrook's eclectic wardrobe: "I know he wears a lot of weird s—. It's a generational thing." Or maybe the proposed age limit for Olympic basketball players: "I think it's stupid."

Kobe Bryant, once a mercurial teenage prodigy, has a new role at the London Olympics:...