Gilbert Burns tests positive for COVID-19, out of UFC 251 headliner vs. Kamaru Usman - MMA Junkie
USA Today
The UFC 251 main event has been derailed: Gilbert Burns has tested positive for coronavirus and is out of his title bout with Kamaru Usman.
https://mmajunkie.usatoday.com/2020/07/ufc-251-gilbert-burns-out-kamaru-usman-title-fight-coronavirus