Sources: Curtis Blaydes tests positive for COVID-19, fight vs. Derrick Lewis called off

COVID-19 has knocked out this weekend's UFC main event.

The Curtis Blaydes vs. Derrick Lewis heavyweight contender bout scheduled for UFC Fight Night in Las Vegas on Saturday is off due "to a positive COVID-19 test," the promotion announced, without specifying who it was that tested positive.

Sources told ESPN's Ariel Helwani, however, that it was Blaydes who tested positive for the coronavirus.

The UFC is hoping to reschedule Blaydes vs. Lewis for UFC 256 on Dec. 12, sources told ESPN, but no deal is done yet.

ESPN has Blaydes ranked No. 3 and Lewis ranked No. 5 in the world at heavyweight.

The scheduled UFC Fight Night co-main event -- a light heavyweight bout between Anthony Smith and Devin Clark -- has been moved up to feature-fight status and will be five rounds instead of three (prelims on ESPN+ at 8 p.m. ET; main card starts on ESPN2/ESPN+ at 10 p.m. ET).

ESPN's Brett Okamoto contributed to this report.