Disaster struck Bellator at the worst possible time on Saturday, as a last-minute hospitalization forced Matt Mitrione to withdraw from his main event contest against Fedor Emelianenko at Bellator 172, leaving the promotion’s tentpole event without its featured attraction just hours before the doors opened at San Jose’s SAP Center.

An ill-timed kidney stone was ultimately the culprit for Mitrione, and on Monday, the heavyweight veteran expressed immense regret for how everything played out.

“It’s really difficult, man,” Mitrione explained on The MMA Hour. “I’m an athlete, I’ve relied on my body my entire life, and for something like this to happen at literally the worst possible time, just hurts my heart. Man, it’s really, really difficult to handle. And the fact that I literally did everything I possibly could, Bellator did everything they possibly could to extend my time frame, trying to help out, and it just got to a point where it wasn’t going to work — man, there’s nothing I could do about it at all.”

The duel between Mitrione, 38, and Emelianenko was slated to be one of Bellator’s most anticipated shows for the first half of 2017, but things fell apart quickly on Saturday morning, when Mitrione woke up and discovered that a weigh-in day sickness had abruptly evolved into a full-blown medical emergency.

“It really started to kick in on Friday, and I didn’t know if I got sick all of sudden, just what the problem was, but it kept magnifying and amplifying,” Mitrione said. “It got to the point where I was absolutely miserable. At weigh-ins, I had to put on a show and be like, ‘hey, I look good,’ because I don’t want Fedor to see this puking, doubled-over-in-agony kind of guy. It just was really difficult, and then it just kept getting worse.

“On Saturday, Bellator was like, ‘look dude, we have to go to the hospital, this thing isn’t right, something’s going on.’ We went to the hospital, told them what’s going on. They said, ‘look, it’s probably kidney stones.’ They hooked me to my IVs to try to flush it out, and then they gave me a CT scan to see what was really going on, and that’s when they saw the stone. The stone hadn’t even passed.”

Mitrione said he found blood in his urine on Saturday morning, which only worsened his concerns before doctors were able to diagnose the problem. By that point, with the clock ticking and just hours left until show time, Mitrione and Bellator officials were thrust into an “excruciating” situation where “the decision had to made at 3:00 pacific time, and at 2:55 I’m strung up to a double IV trying to push this thing through, trying to find some way to get to work,” Mitrione explained.

Mitrione said he and cornerman Chris Lytle even discussed strategies to try and eke out 45 seconds of solid fight time in order to keep the bout against Emelianenko intact, but that ultimately doctors and Bellator officials took the decision out of Mitrione’s hands by canceling the fight.

“I apologized,” Mitrione said. “I was like, ‘dude, I’m so sorry, man. I can’t believe this happened. I’m devastated, man. I’m really sorry.’ I know how much money they put into this, I know how much stock they put into it. I know that was no counter-programming. We were the only show in town. It was a massive, massive fight, and I dropped the ball. It’s just, it sucks. It’s a feeling of absolute tremendous guilt. And then what really sucks, man, is to see every single douchebag on the planet who could possibly create any kind of something, writing something on Twitter, being like, ‘oh you coward, you didn’t even try, you should’ve known months ahead of time.’ Dude, go f*ck yourself. Are you for real?

“This thing, a kidney stone in this situation that came out of nowhere, just cost Bellator millions of dollars. It cost the fight world an incredible fight that I really believe everybody wanted to see (and that people) were really excited about and really hyped. I owe the fans a fight. I owe Fedor a fight. Fedor and I owe the fans a fight. And I’m going to get it taken care of, man. It sucks that I’m going to have a metal rod stuffed in my pee-hole to get this thing taken care of so it never happens again, but I can at least eliminate this from any kind of concern in anybody’s eyes that it’ll never come up again.”

Mitrione said he passed the stone, which was four millimeters in diameter, at a Dallas airport on Sunday while trying to make his way home.

Throughout the process over the weekend, Mitrione also discovered that he currently has six or seven more stones sitting in his right kidney. He plans to undergo surgery on Wednesday in Indianapolis in order to get them removed, and though he will be forced to use a catheter for 2-10 days after the procedure, the surgery is designed to give doctors an opportunity to diagnose why Mitrione is dealing with so many kidney stones in the first place.

After that is taken care of, Mitrione hopes to return to action in the Bellator cage as soon as possible, whether it’s against Emelianenko or not.

“I have not been rebooked, but if Fedor wants to wait until May or June, if that’s what his heart is, then that’s cool. I’m not going to wait that long,” Mitrione said. “I’m going to try to get in there and get some work. So I’m asking Bellator to try to book me as soon as possible, and if we can do that, I’ll pass whatever kind of medicals I need to pass and Bellator will take (care of) all the worries that they have to take, and I understand it and it’s reasonable, so they’ll do everything they have to do and I’ll get it passed, and hopefully I’ll get in there as soon as possible. I’ve already been out for seven months, right? Eight months?

“I don’t want to wait. I compete. I live to compete and to be a father. So for me, I’m going to be a dad all the time, but I don’t do well sitting on the shelf. A rolling stone gathers no moss, so let me work, baby. Let me work. I’m not worried about losing. That’s not a thought in my mind. I feel like I’m better than I’ve ever been in my life and y’all would’ve seen that, and I understand it’s easy to say right now, but I’m pretty damn good.”

Bellator president Scott Coker on Saturday revealed that Emelianenko was targeting a return date in either May or June. So if that’s the timetable the legendary Russian is shooting for, Mitrione is confident that he’ll have more than enough time to fight another opponent in the interim before revisiting the one that got away.

“I believe Fedor wants to fight me, so I believe that fight is on the table,” Mitrione said. “And when Fedor feels prepared, wants to come back, wants to sign a contract to fight whenever, I’m the name he’s going to ask for to be on that contract, and I’m going to be there to sign it again. But this time, I’ll have no kidney stones.”