St-Pierre sprawled on a sparring partner's takedown attempt, trainer Firas Zahabi today told MMAjunkie.com (
www.mmajunkie.com). Then the champ circled away, the injury became apparent.
"After he cooled down, I knew he couldn't fight anymore," Zahabi said. "I've been around, I've seen injuries, and I know that that kind of injury is going to take at least two to five weeks of not standing on it for it to be really good (and) sturdy to fight. That's just me estimating with what I've seen in the past."
As to the exact nature of St-Pierre's injury, Zahabi confirmed that it was a sprain but could provide no further specifics. He wasn't present when the fighter went to the doctor after the training session and received an MRI that confirmed he couldn't compete at the pay-per-view event, which takes place Oct. 29 at the Mandalay Bay Events Center in Las Vegas.
"I don't know what the medical term is," Zahabi said. "I don't know which tendon, or ligament, or whatever is sprained. I'm not a doctor, but I know he's [had] an MRI, he got tested, and he won't be able to fight.