The UFC 251 main event has been derailed by the coronavirus, as Gilbert Burns has tested positive for COVID-19 and is out of his bout with welterweight champion Kamaru Usman.

Multiple people close to the situation informed MMA Junkie on Friday night that Burns (18-3 MMA, 12-3 UFC) has been pulled from his fight with Usman (16-1 MMA, 11-0 UFC), which takes place next week in Yas Island, Abu Dhabi. The fight is expected to be rescheduled at a later date. The people requested anonymity because the UFC has yet to make an official announcement.

Burns traveled from Florida, where he trained for UFC 251, to Las Vegas. The promotion is using the city as a hub to send athletes overseas to Abu Dhabi, testing them for COVID-19 before flying out to the Middle East. Burns’ test result came back positive, as well as his brother and cornerman, Herbert Burns, and coach Greg Jones.

All three men did not board the charter flight departing Las Vegas. Usman also did not board the plane.

News of Burns’ positive COVID-19 test comes on the heels of his Sanford MMA teammate, Aung La N Sang, revealing he’d recently tested positive.

Many thought Usman would fight Jorge Masvidal at UFC 251, but when Masvidal’s contract negotiations went sour, Burns, who has already picked up wins over Demian Maia and Tyron Woodley this year, accepted an offer.

Two other title fights are scheduled for UFC 251: Featherweight champion Alexander Volkanovski’s rematch with former champ Max Holloway and the battle for the vacant bantamweight belt between Jose Aldo and Petr Yan.