The UFC said Saturday night that Cormier suffered a torn adductor in his groin, and a source close to the fighter told ESPN.com that he expects to be back in the gym "in early 2017."
MMAFighting.com first reported Cormier's withdrawal Friday. The 205-pound title fight was supposed to headline the pay-per-view card on Dec. 10 at Air Canada Centre in Toronto.
Johnson (22-5) addressed the situation on Twitter, saying he hopes Cormier has a "full recovery."
I wish nothing but the best for DC and I hope you have a full recovery champ...— Anthony Johnson (@Anthony_Rumble) November 25, 2016
Cormier (18-1) responded to Johnson:
@Anthony_Rumble I left a message for you on ur phone. I apologize. We Will get to rock and roll bruh. Once again my apologies. DC— Daniel Cormier (@dc_mma) November 25, 2016
It is not yet known whether Johnson will remain on the card. The bout was to be a rematch of a May 2015 title fight, when Cormier won the vacant title by submitting Johnson at UFC 187.