TJ Dillashaw, top, pins down Renan Barao during their UFC 173 bantamweight championship bout at MGM Grand Garden Arena in Las Vegas on May 24.Stephen R. Sylvanie
Bantamweight champion T.J. Dillashaw has had to pull out of the main event of UFC 186 in Montreal due to injury.
The UFC says Dillashaw fractured a rib in training Monday.
The 29-year-old American was to defend his 145-pound title on April 25 in a rematch with Brazilian Renan Barao.
There was no immediate word on when Dillashaw might be able to return to action or about a possible new main event for the Montreal show.