UFC middleweight Chris Curtis' gruesome injury at UFC 289 has concerned MMA fans on social media.'Action Man' locked horns against Nassourdine Imavov in a 185-pound clash in the prelims of UFC 289. Curtis was involved in a brutal head-clash in the second round. The collision left a horrific cut on the 35-year-old's eyebrow.Curtis had difficulty seeing from the injured eye which resulted in the fight being declared a no-contest. 'Action Man's teammate and friend Sean Strickland posted a picture of the cut suffered by Curtis.Several concerned MMA fans took to the comments section to share their thoughts on Curtis' injury.Bigg Country@BiggCountry_@SStricklandMMA Man's can't catch a break, that sucks13@SStricklandMMA Man's can't catch a break, that sucksAlfie@AlfieCelentano@SStricklandMMA Chris will be back he is one tough dude and as long as he didnt get an L and hopefully they paid him@SStricklandMMA Chris will be back he is one tough dude and as long as he didnt get an L and hopefully they paid himKieran Shez Wilde@Shezintheshed@SStricklandMMA Worse than what ya see from elbows damn I feel for Curtis… guys a warrior! Legend! Head up champ you will be back!!@SStricklandMMA Worse than what ya see from elbows damn I feel for Curtis… guys a warrior! Legend! Head up champ you will be back!!Chase-Me@ChaseMarrocco@SStricklandMMA Damn and he wanted to keep going ! What a damn beast1@SStricklandMMA Damn and he wanted to keep going ! What a damn beastChris Curtis uploaded an update on his Instagram account where he shared that he received 10 stitches and a possible corneal abrasion as a result of the head clash. The Ohio native then proceeded to apologise to his fans for letting them down.Curtis' fans came out in his support in the comments section and shared motivating words for the 35-year-old.One fan asked 'Action-Man' to focus on healing up while another asked him not to worry about the fight's outcome:"Heal up cowboy.""We believe it. Nothing to be sorry for, come back better action man."Check out a compilation of the fan comments below:Fans show support to Chris Curtis in the comments sectionCurtis' friend Strickland also chimed in on the issue when a Twitter user asked him about the controversial ending. 'Tarzan' shared how he suffered an orbital floor fracture in his fight against Kamaru Usman and thus, was in favor of the fight being stopped midway.Sean Strickland@SStricklandMMAI fought 3 rounds with Usaman with a orbital floor fracture.. getting my head bounced off the mat for 15 minutes not being able to see.... From that experience I'd never let a fighter continue who said they couldn't see... twitter.com/CharlieQuinnMM…Charlie Quinn@CharlieQuinnMMA@SStricklandMMA What do you have to say to the people who think Chris Curtis quit tonight?59224@SStricklandMMA What do you have to say to the people who think Chris Curtis quit tonight?I fought 3 rounds with Usaman with a orbital floor fracture.. getting my head bounced off the mat for 15 minutes not being able to see.... From that experience I'd never let a fighter continue who said they couldn't see... twitter.com/CharlieQuinnMM…Chris Curtis injury: A look into the UFC's no-contest roleUFC@ufcChris Curtis was pleading for the fight to continue. Warrior. #UFC2892503152Chris Curtis was pleading for the fight to continue. Warrior. #UFC289 https://t.co/SQjCfuZAqIThe fight between Nassourdine Imavov and Chris Curtis at UFC 289 was declared a no-contest due to accidental clash of heads. Unfortunately, this outcome is not very rare in recent times.A no-contest outcome happens in the UFC when an official winner cannot be declared due to circumstances outside the athletes' control. This usually happens when an athlete suffers an accidental injury and the fight has not crossed the halfway time-mark. One thing to note is that the blow has to be unintentional. Otherwise, the fighter who lands the strike can be disqualified.One common occurrence of this happening is when an opponent accidentally lands an illegal blow like a groin strike, an eye poke, or a headbutt. If the referee determines that the fighter is compromised due to the unintentional yet illegal strike, the fight can be ruled a no-contest.However, a 'no-contest' does not always come from something that happens during the fight. If an athlete wins a fight but then tests positive for a banned substance shortly after the fight, the contest can be declared a no-contest.One popular example of this is the fight between Jon Jones and Daniel Cormier, where after beating Cormier via TKO, 'Bones' tested positive for turinabol and thus, the fight was declared a no-contest.