Kamaru Usman and Gilbert Burns will not fight next Saturday night for the UFC welterweight championship.

The two men, former training partners, were set to main event UFC 251 on Yas Island, Abu Dhabi in the feature bout to kick off the UFC’s run of ‘Fight Island’ events. Per MMAJunkie, Burns tested positive during his mandatory pre-flight Covid-19 test ahead of his flight to Abu Dhabi.

Burns’ coach Greg Jones’ tests also returned positive. His training partner, Aung La N Sang, announced his own test failure yesterday.

View this post on Instagram

Dear family and friends, I got tested for covid-19 on Monday and the result came back today and I am positive. So my family and I will be quarantining ourselves for the next 14 days. I had a slight fever, congestion, body ache and fatigue on the first two days. Besides that I am blessed that my whole family is doing well. We are really in this together and we will get over this.

A post shared by Aung La Nsang (@aunglansang) on Jul 2, 2020 at 2:21pm PDT

Usman will now be pulled from a card in which his involvement was already far from simple. The champion was originally supposed to meet rival Jorge Masvidal, only for negotiations between Masvidal and the UFC to sour, leading to Burns stepping in as a replacement.

Burns had recently racked up two impressive back to back wins over Demian Maia and former champion Tyron Woodley. This was his first opportunity at a UFC world title.

pic.twitter.com/Odl6aJhCni

— Jorge Masvidal UFC (@GamebredFighter) July 4, 2020

While there will be no late notice replacement for Usman, UFC 251 will continue with two title fights in the form of Alexander Volkanovski vs. Max Holloway, and Petr Yan vs. Jose Aldo for the featherweight and bantamweight belts respectively.