Now Mr. Roberts, 29, was training for a different sport — Fightball, a venture that could be described as street basketball waged in a nightclub, complete with a D.J., a bar and a V.I.P. lounge. Fightball seeks to commercialize one-on-one street basketball, the sport’s rawest form, and repurpose its unregulated intensity for the Instagram era.

Contact is encouraged. During a recent match, a player yanked his opponent’s ankle in the middle of a dunk, causing him to slam to the ground as spectators snapped photos with their phones. After shirt tugs and two-handed shoves, the flagrant gesture was finally called a foul. A $100,000 prize awaits the victor of the three-night tournament, which begins with 16 players. Mr. Roberts would be one of them.