UFC 279's scheduled main event between Nate Diaz and Khamzat Chimaev is in doubt after the latter missed weight by 7.5 pounds on the eve of the fight.

Chimaev and Diaz are scheduled to go toe-to-toe on Saturday in Las Vegas but that bout is in jeopardy after the Swedish fighter hit the scales at 178.5 pounds, above the non-title welterweight limit of 171 pounds – which Diaz weighed at.

Further complicating the matter is the fact 37-year-old Diaz will become a free agent following the weekend, with Saturday's fight scheduled as his last with UFC, and it is unknown what would happen with his contract if the fight was cancelled.

It continues a week that has been far from what UFC planned, with Thursday's press conference having been cancelled after Chimaev got into a skirmish with Kevin Holland, who is due to face Daniel Rodriguez on the card.

Co-main event fighters Tony Ferguson and Li Jingliang both made weight for their bout, with Holland and Rodriguez also meeting weight.

With the main card featuring four fights outside of Chimaev v Diaz, the show could go ahead without the main event, though Ferguson has been touted to fight Diaz instead.

A further eight bouts are scheduled on the early preliminary card and the preliminary card.