UFC’s Fights Outside Octagon Include Renewed Talk About Union

Some of the biggest fights for mixed martial arts professionals are going on outside the octagon.

An existing push to unionize competitors got renewed buzz in December when the Ultimate Fighting Championship, the world’s largest MMA organization, exposed athletes to California’s “jock tax” by changing the venue for an event at the last minute. UFC President Dana White’s insistence that fighters cover the taxes, saying it was “either that or not fight,’' came months after the circuit reached a five-year, $1.5 billion broadcast deal with ESPN.

To former UFC fighter Leslie Smith, who works with professional MMA association and union ...