A domino effect of difficult decisions shelved one of the most anticipated fights of 2012. This we know. And although much of the fallout from last week's tumult focused on Zuffa's unprecedented cancellation of UFC 151 and Jon Jones' controversial opt-out of an event-saving contest with Chael Sonnen, the first shoe to drop was still Dan Henderson's.

"This is the first time in 15 years -- or ever, I guess I should say -- I backed out of a fight," Henderson reflected this week.

That is not something to take lightly. Henderson needed a moment to remember the last time he couldn’t do what he’s always done. (Shoulder surgery kept him from a wrestling world championships a lifetime ago.)

As the former Pride and Strikeforce champion mulled these past few weeks over the extent of a destabilizing knee injury, when the right time was to inform his promoter and what to do if, for as much as he wanted to hang in there, doctors advised against it, Henderson’s unflinching mind held out hope he "could still fight and that's all that mattered."

Yet days before his 42nd birthday, Henderson's body had not met the mind-over-matter challenge. It was over. He couldn't engage Jones in Las Vegas on Sept. 1, and down went the first domino. Then another. And another.

"I struggled for a few days but really hard for the last couple days," he said of the final decision. "I tried to get a hold of [UFC president] Dana [White] last Monday. Got a hold of him on Tuesday, and they flew me out to Vegas. That whole two or three days [were] tough to figure out, and even then after I met with his doctors I was still on the fence with it. I went back and really tried and gave it a tougher workout to see where I was at.

"It was tough to come to terms with me not being able to fight."

Henderson had no inclination that his decision would lead to the demise of UFC 151. He figured Zuffa, even on short notice, could do what it’s done in the past. Find a replacement. Move a fight around. Something. Anything. And although blame was cast like a kid tossing mashed potatoes in a cafeteria lunch fight, Henderson retained no sense of culpability, even if he could have given Zuffa a fortnight to find an alternative.

Rather than tell Zuffa early on, he chose to keep the news sequestered to his camp. Henderson said doctors told him the MCL tear was manageable. A little rest, and he might actually make the date. Being banged up was nothing new to the man, so he treated a structural injury as he might a bump, a bruise or busted-up nose. Also, Henderson didn't want word getting out, which it did not, he claimed, until the UFC was finally brought into the loop.

"The minute I told UFC and went and told Dana is when everyone asked questions," Henderson said. "That's one of the reasons I kept it to myself and my camp only. I have to commend my guys for doing a pretty good job of not opening their mouths knowing I was hurt."

"I didn't feel responsible. I felt horrible that I had to back out. It's not something I wanted. I had no idea what I could have done to change that, other than not get hurt."

Among the most accomplished fighters in MMA history, Henderson (29-8) owes nothing to anyone. Just the same, he doesn't feel as though he's owed much, including the guarantee that, when healthy, a title shot will be waiting for him. That set of circumstances didn't enter his mind, he said, when the decision became inevitable.

"I didn't ask, 'Hey, what's going to happen if I pull out?'" he said. "That wasn't what it was about. It was about whether I could fight or not. I didn't need to know. In my mind, I didn't have the right to know. I didn't want to know if my fight was guaranteed if I pulled out, making it easier for me to pull out. I didn't really want to know what was going to happen. I wanted to make sure I made the decision based on the fact if I could fight or not. Even now it's unknown what will happen with my next fight."

Henderson is expected to return without surgery. He'll undergo two to three weeks of knee immobilization, then rehab. Meanwhile, Jones will fight Vitor Belfort on Sept. 22 in Toronto. "I'm not really interested to see the fight, and I'm a fan of both guys," Henderson said. "I don't think the fans are going to be real interested."

Jones' decision to turn down Sonnen isn't the way Henderson would have played it.

"The bottom line is, if I was in shape ready to fight on a date and I'm healthy, I'll fight anyone at that point, especially if I'm supposed to be defending a belt if I'm the top guy in a weight class," he said.

Living at the top is familiar territory for Henderson. For now, though, he'll reside in purgatory, subject to the whims of an aged body, his promoter and the rigors of rehabilitation.

It's fight week, but there isn't a fight to be found.

"I don't know what I'm going to do this weekend," Henderson said. "I might take a little vacation since I didn't really have a summer."