The moment he took the pills, Chris Leben knew he'd get caught. He knew it was a mistake, like he knew he'd be drug-tested before his middleweight fight against Mark Munoz in UFC 138, like he knew the Oxycontin he popped wouldn't be out of his system by then.
For Leben, 32, the sickness didn't develop overnight or over the course of a training camp. It had been years in the making, a slow battle fight fans have watched from a distance since he made his debut on the first season of the UFC's long-running reality show, "The Ultimate Fighter."
Back then, Leben was the hard-drinking brawler who got by on guts and raw emotion as much as skill. It made him an early fan favorite, but it wasn't something he could turn off once he stepped out of the cage.
Leben's UFC career has been marred with arrests for driving under the influence and suspensions for steroids and prescription painkillers. Through it all, the UFC has stuck with him even while other fighters have been given their walking papers for far less egregious offenses.
Now, after a year suspension following a positive test for Oxycontin in November 2011, Leben (22-8 MMA, 12-7 UFC) returns Saturday against Derek Brunson (9-2 MMA, 0-0 UFC) in UFC 155 (pay-per-view, 10 p.m. ET).
For Leben, the fight comes with more nerves than usual after a long layoff and tumultuous year. At the same time, he says, "I want to remind everybody who I am and what kind of force I am inside the octagon."
One man who needs no reminder is UFC President Dana White, who says he has kept Leben around through his substance abuse struggles because "he's a guy I like and respect."
"He's had personal problems for a long time that he's had to deal with, but I don't consider this a second or third chance or anything like that," White said in an e-mail. "He's always exciting, and people like watching him fight, including me."
Maybe that's why, instead of firing Leben after his latest failed drug test, the UFC paid to send him to a 30-day rehab program.
Leben followed that with regular outpatient counseling sessions, he says, where he's learning to deal with life on life's terms.
"It's a one-day-at-a-time sort of thing," Leben says. "It doesn't matter how far down the road you are, we're all the same distance from the ditch. I know what happens in my life when I drink. I know how fast things destruct for me."
The cravings for alcohol and drugs? Those are still there, Leben says. He was using painkillers for physical and emotional pain, and "looking back, my intake really reflected how well I was doing in my personal life."
These days he's sober, but he also has to adjust his approach to the sport.
That reckless audacity he has always fought with came from a dark place inside, but so did the substance abuse problems that came with it.
"When I first started this sport, my motivation was proving that I was tough and I was worth something," Leben says.
Now the fight has changed. This time it's not one he can afford to lose.