Dana White and Jeff Novitzky explain why UFC 232 is being moved to Los Angeles after Jon Jones' test results show a presence of metabolite from his 2017 test. (2:35)

UFC President Dana White shook up the MMA world on Sunday when he appeared on SportsCenter to announce that UFC 232 on Dec. 29 will be moved from Las Vegas to Los Angeles. The highly anticipated card is headlined by Jon Jones and Alexander Gustafsson competing for the UFC light heavyweight belt.

The move is based on licensing. The United States Anti-Doping Agency (USADA) reported an atypical finding of a drug test Jones submitted on Dec. 9. USADA, however, ruled that the trace amount found in Jones' system is consistent with "residual amounts" of a July 2017 test, meaning the low amount does not suggest that Jones readministered a parent drug.

"Both USADA and worldwide anti-doping experts told us this was not a reingestion of a prohibited substance. It was remaining effects from the July 2017 positive test -- for which he was already sanctioned," Jeff Novitzky, UFC's vice president of athlete health and performance, told ESPN. "And probably more importantly, he retains no performance-enhancing benefits from the small presence of the substance."

The Nevada State Athletic Commission would not grant Jones a license, so to keep him on the card, the UFC moved the event to Los Angeles.

When news broke, MMA fighters took to social media to express their opinions on the late-notice change.

He tested positive again! - Daniel Cormier (@dc_mma) December 23, 2018

I'm focused on achieving my ultimate goal of reclaiming my Light Heavyweight title. I have willingly submitted to every USADA test in the lead up to this fight and USADA has confirmed what I've been saying all along, that I'm a clean athlete. I sincerely thank the California — Jon Bones Jones (@JonnyBones) December 24, 2018

State Athletic Commission and Andy Foster for doing the right thing and supporting me through this process. I cannot wait to fight Alex Gustafsson this Saturday December 29th at the Los Angeles Forum in Inglewood. — Jon Bones Jones (@JonnyBones) December 24, 2018

Can't bend me, can't break me. #Champion2018 — Jon Bones Jones (@JonnyBones) December 24, 2018

Now we all understand why u didn't take the Wada test! U can be on rocket fuel,, I'll still gonna finish u Jon! #andnew #ufc232 — Alexander Gustafsson (@AlexTheMauler) December 24, 2018

I'm always clean. I train and drink Modelo. https://t.co/V9e2YMeYeB - Stipe Miocic (@stipemiocic) December 24, 2018

Well... wasn't expecting to pay California state taxes this Holiday season. #UFC232 — Amanda Nunes (@Amanda_Leoa) December 24, 2018

Remember that time Dana said @jonjones would never main event again.... um yeah - Ben Askren (@Benaskren) December 24, 2018

I've always been very defensive of the criticisms against ufc but I'm really not proud to be a part of this organization today. - Matt Brown (@IamTheImmortal) December 24, 2018

A pinch of salt in an Olympic size swimming pool still showing up in your text results 1.5 years later 🧐 #ufc232 — JIMI MANUWA (@POSTERBOYJM) December 24, 2018

Or maybe a fighter on the card that had to find out through the internet... https://t.co/qNmwMdFSlN - Megan Anderson (@MeganA_mma) December 23, 2018

Shoutout to all the UFC employees working hard on Christmas Eve & Day ������ You all are the best - Cub Swanson (@CubSwanson) December 24, 2018

17 picograms of ostarine got me 2 years. - "Filthy" Tom Lawlor (@FilthyTomLawlor) December 23, 2018

Meanwhile back at my air bnb in Vegas.... #ufc232 pic.twitter.com/9mDZvMEcoP - Michael Chiesa (@MikeMav22) December 24, 2018

USADA is a joke. Small trace amount from 2017 trigged a positive test? UFC has to move the entire event from Vegas to LA due to "holidays" for NASC. Oh cool. Nothing fishy AT ALL. ����‍♂️������ https://t.co/xJ5OaAUZbn - Brendan Schaub (@BrendanSchaub) December 24, 2018

Why am I not surprised... pic.twitter.com/JTmmDOXFsc - Anthony Smith (@lionheartsmith) December 24, 2018