The UFC has radically transformed from its inception in the early '90s. The promotion began as a no holds barred fighting league that held events only once or twice a year, mainly due to issues relating to location. Nowadays, it's a billion-dollar company that has deals with ESPN and is arguably the fastest-growing league on the planet.

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With that success, has come more events. The UFC is generally running a show every single week, and unlike other leagues such as the NFL or NBA, there's no offseason. However, the UFC sometimes fails at putting a show on a given week - they've failed to do so 9 times, to be exact. Most events failed for radically different reasons.

9 UFC 151

UFC 151 has been dubbed as the event that Jon Jones killed. 'Bones' was scheduled to fight former PRIDE and Strikeforce champion Dan Henderson in the main event, as the champion looked to get another title defense under his belt. However, a week before the event, Henderson got injured and was forced to pull out of the fight.

Top middleweight contender Chael Sonnen stepped up, and the UFC tried to run with it. The issue is, Jones' team told him that accepting the short-notice bout would be the biggest mistake of his career. As a result, 'Bones' turned the fight down, and with no possible replacement bouts, the UFC canceled the whole card.

8 UFC 176

Unlike UFC 151, UFC 176 had a great undercard. It was a stacked pay-per-view that featured many top contenders on the event, such as Jacare Souza, Gegard Mousasi, Tony Ferguson, Gray Maynard, and more. On paper, it was arguably the UFC's best card of 2014.

However, the event was canceled. Less than a month out from the event, champion Jose Aldo pulled out of his headlining bout with Chad Mendes. The UFC was unable to find a replacement for the main event and decided that none of the undercard bouts were worthy of the PPV headlining role.

7 UFC Fight Night: Lamas vs. Penn

When B.J. Penn announced he was coming out of retirement in 2016, they decided to give him a big return fight. The former dual-weight champion was matched up with top featherweight contender Ricardo Lamas, in the promotion's second trip to the Philippines.

Just two weeks out from the event, Penn had to pull out due to injury. The UFC decided to cancel the card as a result, as they couldn't find a replacement and didn't think another fight was main event worthy. They did have a co-main event lined up between Derrick Lewis and Marcin Tybura, who ended up main eventing a year and a half later. However, they decided that the heavyweights wouldn't suffice for this one.

6 UFC 233

UFC 233 is a card that was a victim of circumstance. The card was set for the week after the UFC's first card on ESPN, and the promotion originally had Henry Cejudo vs. T.J. Dillashaw set for the PPV card. However, they had issues finding a suitable main event for their ESPN debut.

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As a result, UFC 233 was canceled, and they moved the PPV main event a week back, and essentially made the fight night that month's PPV event. UFC 233 was canceled, but in-name-only.

5 UFC Fight Night: Woodley vs. Edwards

The first COVID-19 cancellation came in March 2021. The card was originally scheduled to be held at the O2 in London, with top welterweights Tyron Woodley and Leon Edwards squaring off. The week before, the promotion was forced to hold its Brazil fight night event without a crowd and prepared that this event would be the same way.

However, after the U.K. government ruled that the UFC couldn't hold the event, they moved it back to the U.S. They tried to scramble to fight a place to hold the event before they eventually canceled it five days before it was scheduled to take place.

4 UFC on ESPN: Ngannou vs. Rozenstruik

The second COVID-19 hit was an ESPN headlining bout between Francis Ngannou and Jairzinho Rozenstruik. The co-main event was scheduled to be a bantamweight showdown between Cody Garbrandt and Raphael Assuncao.

This one got canceled thanks to COVID as well. However, this one actually had the main and co-main event happen, just at a later date. Ngannou knocked out Rozenstruik at UFC 249, and Garbrandt knocked out Assuncao at UFC 250 a month later.

3 UFC Fight Night: Overeem vs. Harris

The third of the pandemic cards was a Portland heavyweight clash between Alistair Overeem and Walt Harris. The bout was an anticipated one, as Overeem was nearing the end of his UFC run, and Harris had lots of momentum heading in.

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This event got canceled at the same time as the previous two entries. Thankfully, this main event ended up happening down the road. The two met a month after the originally proposed date, and Overeem won the wild bout via second-round TKO.

2 UFC Fight Night: Smith vs. Teixeira

The latest of the canceled cards, this event had the plug pulled only five days out. Granted, nobody thought it was going to happen, but it was officially canceled only just a few days before it was scheduled in Nebraska.

Fans once again missed out on live MMA thanks to COVID-19 for this event. Thankfully, the main event between Anthony Smith and Glover Teixeira did proceed a month later, with the Brazilian pulling out the win.

1 UFC Fight Night: Hermansson vs. Weidman

The most recent card cancellation came in May 2020. Once again thanks to the ongoing pandemic, Oklahoma City fans missed out on a headlining bout between Jack Hermansson and Chris Weidman.

Unfortunately, this matchup was never revisited. Hermansson was instead slotted into a matchup with Kelvin Gastelum which he won in July, and Weidman defeated Omari Akhmedov in August.