The fight was billed as a potential No. 1 contender's bout, with the winner moving on to face UFC middleweight king Anderson Silva.
That's when Murphy's Law (the old adage that whatever can go wrong, will go wrong) jumped up and took a big bite out of Munoz's dreams.
Earlier in 2012, Munoz was set up for a fight against Chael Sonnen at UFC on Fox 2. With a win he would have assuredly received a shot at the middleweight title, but an elbow injury forced him out of the fight just days before it was set to take place.
So when the injuries started mounting ahead of his scheduled bout against Weidman, Munoz refused to pull out of another fight and risk losing even more ground in the contenders' race.
"You saw my physical stature. It just wasn't me. I wasn't able to run, I cut weight totally wrong, it was just totally bad," Munoz told Bleacher Report recently. "It was an adversity stricken camp, but I still fought. I didn't want to be that guy to back out twice in a row."
What resulted really became a worst-case scenario for the former NCAA wrestling champion.
Munoz lost badly.
Weidman finished the fight in the second round after landing a standing elbow strike before blasting away with punches as Munoz lay virtually motionless on the canvas.
The defeat was the last thing Munoz wanted, much less what he needed for his career to move forward. Following the fight, a wave of depression washed over him as he gained massive amounts of weight while dealing with an injury.
Now, almost exactly a year later, the former WEC fighter is on the cusp of his return to action. Despite the fact that he knows Weidman didn't come close to seeing the best version of Mark Munoz, it was a valuable lesson learned.
"I was in a dark place, but I don't take any of that back," Munoz said. "Because through that injury, I was able to correct a lot of things I was doing wrong.
"I definitely learned. It gave me perspective through that whole thing. They say adversity is the testing of your character, and I really was tested, and I came out a better person because of it."
Munoz managed to find the strength to return to the gym and drop the extra weight. He looks to serve notice to the middleweight division he's back starting with his fight against Tim Boetsch this weekend.
He will certainly have extra motivation, because the man who defeated him in his last fight will be competing in the main event. Weidman faces Silva for the 185-pound title, but whether there is gold on the line or not, Munoz would love the chance to avenge that loss.
It's not about the typical fighter rhetoric where someone just can't get past a defeat. For Munoz, it's more to do with the fact that he didn't and couldn't come close to giving Weidman his best that night.
"I didn't come in there 100 percent at all by any means, not even close. So I'd love to have a rematch, if they should grant me one," Munoz said. "I would love to fight him and show a different person inside the Octagon. It does eat at me because I am a competitor and I didn't show what I can do. It was really depressing to see that performance."
Before he can even begin to contemplate a second fight with Weidman, Munoz knows everything stops until after he beats Boetsch. This bout is Munoz's title fight because he faced so many demons to even get to this point that anything less than victory is just unacceptable.
The last year has been hard on Munoz, but he can wash it all away with the right kind of performance at UFC 162.
"Tim Boetsch is very tough, and I've got nothing but respect for him and what he's done in the sport and how he's competed. For the most part, I've been in the top 10 most of this year; even having not fought, I haven't fallen out of the top 10. They just see me as that type of fighter, and I truly believe I am in the top 10 or even the top five still at this point.
"Jumping into the deep water, swimming with the sharks, I'm definitely ready," said Munoz. "I'm definitely ready to take on Tim Boetsch and show what I've learned in this last year."
Damon Martin is a Featured Columnist for Bleacher Report, and all quotes were obtained firsthand unless otherwise noted.