UFC star Glover Teixeira has tested positive for COVID-19 ... and now, his main event fight with Thiago Santos is officially postponed.
Glover and Thiago were supposed to throw down at UFC Fight Night on Sept. 12 -- but Glover's COVID test came back positive on Wednesday, screwing up those plans.
The good news ... Glover's camp says the 40-year-old Brazilian legend is feeling 100%.
UFC is now gunning to re-book the fight for Oct. 3 -- but it would no longer be a 5-round main event, according to ESPN.
Glover and Thiago are two of the best light heavyweights in the world.
UFC has Glover ranked is the #4 light heavyweight contender -- coming off a dominant victory over Anthony Smith back in May.
36-year-old Santos -- the UFC's #2 ranked light heavyweight contender -- last fought against Jon Jones back in July 2019, when he suffered major injuries to both knees in a 5-round loss.