In combat sports, injuries are a part of the process of putting together fights. However, the UFC seems to have been struck harder than usual with injures over the first half of 2012.
Already, three title fights have been impacted by injuries, while a heavyweight tilt between Junior dos Santos and Alistair Overeem was also cancelled due to a failed drug test.
The two biggest stars in the sport, middleweight champion Anderson Silva and welterweight champion Georges St-Pierre have still not competed at all in 2012 due to injuries. Silva is set to return against Chael Sonnen in July, but there's still a possibility St-Pierre's knee injury could keep him out of action until 2013.
With the year almost halfway over, let's take a look back at all the fights that have been lost due to injuries over the past six months.
Mark Hunt vs. Stefan Struve
Coming off a big knockout win over Cheick Kongo, Mark Hunt was set up for an important fight with Stefan Struve at UFC 146 that would have likely set the winner up for a fight with a heavyweight contender.
However, just 10 days before the event, Hunt was forced out of the bout due to injury. Having just knocked out Pat Barry three weeks prior, Lavar Johnson stepped in to replace Hunt on the May fight card.
Struve ended up submitting Johnson with a first-round armbar, but the win didn't give him the boost it might have had he had the chance to compete against the more seasoned veteran in Hunt.
Antonio Rodrigo Nogueira vs. Cheick Kongo
Refusing to submit to a nasty Frank Mir kimura left Antonio Rodrigo Nogueira with a broken arm in his most recent fight. Nogueira was expected to return against Cheick Kongo at UFC 149, but the Brazilian was not able to fully recover from his arm injury in time.
Shawn Jordan has replaced Nogueira and will meet Kongo at the July event.
Gabriel Gonzaga vs. Roy Nelson
After returning to the UFC with a win, Gabriel Gonzaga was given the chance to make a big move against a borderline contender in Roy Nelson. However, an injury led to Gonzaga's removal from the UFC 146 fight.
Dave Herman replaced Gonzaga on the fight card, but he was knocked out by Nelson in less than one minute.
Rob Broughton vs. Ednaldo Oliveira
An injury to Rob Broughton gave Gonzaga the chance to return to the UFC in January.
Utilizing the strong jiu-jitsu game that he had strayed from in his prior stint with the UFC, Gonzaga submitted Ednaldo Oliveira in the first round and earned himself some job security with the world's premier MMA organization.
Antonio Rogerio Nogueira vs. Alexander Gustafsson
Following his knockout win over Tito Ortiz, Antonio Rogerio Nogueira was set up for an intriguing fight against up-and-coming light heavyweight Alexander Gustafsson. However, about one month ahead of UFC on Fuel TV 2, Nogueira suffered a knee injury and was replaced by Thiago Silva.
Silva was pulled from a bout with Igor Pokrajac, who ended up fighting Fabio Maldonado and winning a controversial decision.
Gustafsson proceeded to beat Silva impressively in a unanimous decision, but the win over a fighter who had not competed in more than one year may not have had that same impact that a win over Nogueira could have had.
Thiago Silva vs. Mauricio Rua
Despite the loss against Gustafsson, Silva was given an even tougher opponent in Mauricio "Shogun" Rua for his next fight. An injury prevented Silva from competing in that matchup at UFC 149, though.
Following his removal from the bout, Silva replaced by Vera, who was pulled from fight with James Te Huna. Te Huna will now meet Joey Beltran, who will return to the UFC as a light heavyweight after being cut from the organization as a heavyweight not long ago.
The bout between Rua and Vera has since moved to UFC on Fox 4, where it will serve as the fight card's main event.
Chad Griggs vs. Phil Davis
After a loss to Travis Browne in his UFC debut, Chad Griggs opted to make a move to the light heavyweight division, where he was expected to meet Phil Davis at UFC on Fox 4.
However, Griggs suffered an injury and has been replaced by UFC newcomer Wagner Prado.
Brandon Vera vs. Thiago Silva
After a January 2011 win over Vera, it was discovered that Silva had cheated a pre-fight drug test. As a result, Silva's win was overturned to a no-contest, and he was suspended for one year.
Once Silva had served his suspension, the UFC set up a rematch between Silva and Vera. However, Vera was injured and replaced by Igor Pokrajac.
Silva was later pulled from his fight with Pokrajac to replace Nogueira against Gustafsson. As previously mentioned, Silva came up short against Gustafsson in his return to the Octagon, losing the fight by unanimous decision.
Jorgen Kruth vs. Cyrille Diabate
Scheduled to make his debut with the UFC at UFC on Fuel TV 2, Jorgen Kruth was injured and replaced by fellow UFC newcomer Tom DeBlass. Cyrille Diabate proceeded to beat DeBlass in a decision.
Fabio Maldonado vs. Caio Magalhaes
After visa problems forced Stanislav Nedkov out of a UFC 142 fight with Maldonado, Caio Magalhaes stepped in as a replacement. However, Maldonado was later injured, forcing Magalhaes off of the card completely.
Mark Munoz vs. Chael Sonnen
Heading into a bout with Chael Sonnen that could have earned him a middleweight title shot, Mark Munoz was injured and replaced by Michael Bisping.
The Munoz injury gave Bisping the opportunity to prove himself as a top contender at UFC on Fox 2. While he lost to Sonnen, Bisping kept the fight very close and showed he could be closing in on a championship bout in the near future.
Michael Bisping vs. Tim Boetsch
After his loss to Sonnen, Bisping was matched up against the rising Tim Boetsch. Unfortunately, Bisping was forced out of the UFC 149 bout due to injury and has been replaced by former Bellator champion and UFC newcomer Hector Lombard.
Brian Stann vs. Hector Lombard
Lombard was initially expected to meet Brian Stann at UFC on Fox 4. However, Stann was injured, and Lombard ended up being pulled from card to fight Tim Boetsch at UFC 149.
Vitor Belfort vs. Wanderlei Silva
Coaches of the first TUF season in Brazil, Vitor Belfort and Wanderlei Silva were scheduled to fight at UFC 147. Recently, Belfort was removed from the fight due to injury and replaced by Rich Franklin.
Initially scheduled for a fight against Cung Le, Franklin replaced by Patrick Cote, who will be making his return to the UFC after being released from the organization not long ago.
Jared Hamman vs. Kyle Noke
Injured prior to UFC on FX 2, Jared Hamman was pulled from his fight against Kyle Noke, which opened the door for Andrew Craig to step in as a replacement.
Taking advantage of an injury Noke suffered during the fight, Craig was able to walk away with a decision win in his UFC debut.
Georges St-Pierre vs. Nick Diaz
At UFC 143, Georges St-Pierre was originally supposed to fight Nick Diaz. However, St-Pierre injured his knee and was forced to withdraw from the fight, resulting in a interim title bout between Diaz and Carlos Condit.
Condit defeated Diaz, who subsequently announced his retirement from the sport. While many still believe Diaz will return at some point, St-Pierre's injury led to the retirement of one of the sport's most intriguing figures.
Jon Fitch vs. Aaron Simpson
After losing to Ronny Markes in his most recent fight, Aaron Simpson chose to make a move to the welterweight division and was pegged to meet Jon Fitch at UFC on Fuel TV 4.
Fitch was injured, however, and replaced by Kenny Robertson. Simpson won't have the same chance to make a big splash in the 170-pound division, but he should now have a more sure route to victory in his first fight as a welterweight.
Siyar Bahadurzada vs. Erick Silva
Rising welterweight contenders Siyar Bahadurzada and Erick Silva had been scheduled to fight at UFC 142, but Bahadurzada suffered an injury prior to that matchup and was replaced by Carlo Prater.
Silva ended up losing to Prater due to a disqualification for landing punches to the back of his opponent's head. Silva has since rebounded with a win over Charlie Brenneman and could find himself fighting Bahadurzada eventually.
Thiago Alves vs. Yoshihiro Akiyama/Siyar Bahadurzada
A UFC 149 fight between Thiago Alves and Yoshihiro Akiyama has turned into a bout between Bahadurzada and Chris Clements.
Akiyama was first injured and replaced by Bahadurzada. Then, Alves was hurt and supplanted by Clements.
Paulo Thiago vs. Mike Pyle
Paulo Thiago was expected to meet Mike Pyle in his home country of Brazil at UFC 142. However, Thiago was injured and replaced by Ricardo Funch, who ended up suffering a first-round knockout loss to Pyle.
Rick Story vs. Rich Attonito/Papy Abedi
At the upcoming UFC on FX 4, Rick Story will fight Brock Jardine, who was the third selection as an opponent for the welterweight contender.
Story's original opponent, Rich Attonito, was replaced by Papy Abedi due to injury. Abedi was also forced off of the card and finally replaced by Jardine.
Matt Riddle vs. Luis Ramos
Matt Riddle had been scheduled to fight Luis Ramos at UFC on FX 4, but an injury forced him out of the fight and allowed Matt Brown to step in as a replacement.
George Sotiropoulos vs. Takanori Gomi
Coming off of back-to-back losses, George Sotiropoulos was scheduled to enter enemy territory against Takanori Gomi at UFC 144 in Japan.
Sotiropoulos was injured, though, and replaced by Eiji Mitsuoka. Gomi went on to knock out fellow Japanese fighter Eiji Mitsuoka.
Matt Wiman vs. Mark Bocek
Scheduled to fight Mark Bocek at UFC 145, Matt Wiman was injured and replaced by John Alessio. While Alessio got his chance to return to the UFC, Bocek came away with the lopsided decision victory.
Evan Dunham vs. Edson Barboza
Originally, Edson Barboza was scheduled to meet Evan Dunham at UFC 146. However, an injury gave Jamie Varner an opportunity to return to the Octagon by replacing Dunham.
Varner made the most of his chance by beating the up-and-coming Barboza via first-round knockout.
Paul Sass vs. Evan Dunham
In addition to being forced out of a matchup himself, Dunham lost an opponent due to injury for his UFC on Fox 2 appearance.
Paul Sass was replaced by Nik Lentz, who Dunham proceeded to beat by technical knockout due to a cut. While it was a unfortunate ending, Dunham's fight with Lentz was very entertaining and earned him Fight of the Night honors.
Tony Ferguson vs. Dennis Hallman/Thiago Tavares
Tony Ferguson had his opponent changed twice prior to his fight against Michael Johnson at UFC on Fox 3, where he suffered the first loss of his UFC career.
Ferguson's original opponent, Dennis Hallman, was replaced by Thiago Tavares, who also ended up getting injured and replaced by Johnson.
Yves Edwards vs. Donald Cerrone
When Yves Edwards was forced out of his UFC on Fuel TV 3 fight with Donald Cerrone, many thought the UFC had put together an even better fight for Cerrone against slugger Jeremy Stephens.
However, Cerrone dominated Stephens for three rounds and won the fight via lopsided decision.
Paul Taylor vs. Anthony Njokuani
Out of action for more than one year, Paul Taylor was expected to return against Anthony Njokuani at UFC on Fuel TV 4. However, Taylor suffered another injury and has been replaced by Rafael dos Anjos.
Cody McKenzie vs. Michael Johnson
At UFC on Fox 2, Michael Johnson actually benefited from a late opponent change. An injury to Cody McKenzie set Johnson up for a fight with a more respected opponent in Shane Roller.
Johnson won against Roller via decision in a fight that moved him much farther up the lightweight ladder than he would have with a win over McKenzie.
Aaron Riley vs. Cody McKenzie
After being forced out of his fight with Johnson, McKenzie was set to fight Aaron Riley at UFC on Fuel TV 3. Nonetheless, Riley was injured and replaced by Marcus LeVesseur, who McKenzie was able to beat via submission.
Jose Aldo vs. Erik Koch
Expected to defend his featherweight title at UFC 149, Jose Aldo was hurt and forced out of his fight with Erik Koch, who has said he plans on waiting for Aldo to heal despite only earning a title shot with a narrow decision win over Jonathan Brookins.
Leonard Garcia vs. Tiequan Zhang
Scheduled to fight Tiequan Zhang at UFC 144, Leonard Garcia was injured and replaced by Issei Tamura, who proceeded to knock out Zhang in impressive fashion. Tamura is now moving to the bantamweight division, where his power could turn him into a title contender at some point.
Pablo Garza vs. Josh Grispi
Pablo Garza was set to return to the Octagon at UFC on Fox 4, but an injury will delay his chances of rebounding from a loss to Dennis Bermudez. Instead, Josh Grispi will now face off against Rani Yahya.
Robert Peralta vs. Mackens Semerzier
At UFC on FX 2, a late change of opponents may have cost Mackens Semerzier his spot on the UFC's roster. After Robert Peralta was replaced by Daniel Pineda as Semerzier's opponent, Semerzier was defeated and subsequently released from his contract with the world's top MMA organization.
Akira Corassani vs. Jason Young
Following his appearance on TUF, Akira Corassani was expected to make his official UFC debut at UFC on Fuel TV 2. Sadly, Corassani was hurt, allowing Eric Wisely to step in as a replacement. Jason Young went on to defeat Wisely in a unanimous decision.
Dominick Cruz vs. Urijah Faber
One year after their rematch at UFC 132, bantamweight champion Dominick Cruz and Urijah Faber were supposed to follow their appearance as coaches on TUF with a rubber match at UFC 148.
However, during filming of TUF, Cruz suffered a knee injury and was replaced by Renan Barao, who will compete against Faber for an interim title.
Eddie Wineland vs. Johnny Bedford
An injury first caused Eddie Wineland to be replaced by Mitch Gagnon in a fight against Johnny Bedford at UFC on Fox 2. However, the bout between Bedford and Gagnon was ultimately cancelled due to visa issues for the Canadian Gagnon.
Mike Easton vs. Yves Jabouin
A bout between Mike Easton and Yves Jabouin was scheduled for UFC on Fuel TV 3, but an Easton injury caused Jeff Hougland to step in as a replacement.
Jabouin won by unanimous decision, handing Hougland his first UFC loss.
Jimmy Hettes vs. Steven Siler
After a big win over Nam Phan, Jimmy Hettes was set to fight Stephen Siler at UFC on FX 4. Unfortunately, Hettes suffered an injury and has been replaced by UFC newcomer Joey Gambino.
Byron Bloodworth vs. John Albert
After losing to Mike Easton in his UFC debut, Byron Bloodworth was scheduled to return at the most recent TUF finale, but an injury forced him out of his bout against John Albert, who ended up losing via a controversial submission against Erik Perez.
Johnny Bedford vs. Nick Denis
Johnny Bedford was expected to fight Nick Denis in his first fight since winning at the TUF 14 Finale, but an injury caused him to miss the event. Bedford was replaced by Roland Delorme who defeated Denis in an upset.
Ken Stone vs. Edwin Figueroa/Francisco Rivera
For his upcoming fight at UFC on FX 4, Ken Stone has had to prepare for three different opponents. Initially, Stone was supposed to fight Edwin Figueroa, who was replaced by Francisco Rivera. Recently, Rivera was also injured and will be replaced by Dustin Pague, who will have fought twice in a two-week period.
Azamat Gashimov vs. Alex Soto
Azamat Gashimov was supposed to make his UFC debut at UFC on Fuel TV 3, but an injury led to Gashimov being replaced by Francisco Rivera. Rivera went on to fight Alex Soto, who he beat by unanimous decision.
Darren Uyenoyama vs. John Dodson
After beating Norifumi Yamamoto in his UFC debut, Darren Uyenoyama was scheduled to make his flyweight debut at UFC on Fox 3 against John Dodson.
Uyenoyama was injured, though, and replaced by Tim Elliott, who ended up being defeated by Dodson in a decision.
While the injury delayed Uyenoyama's first fight at 125 pounds, it allowed the UFC to add some depth to its newest division.