Georges St-Pierre's road back to the Octagon is suddenly a lot bumpier.
The former UFC welterweight champion, currently on hiatus from mixed martial arts but still training with an eye to a future return, revealed Thursday that he requires knee surgery.
"Tore my left ACL in training. Surgery in a few days," St-Pierre said via Twitter. "Rehab, pain, hard work, no shortcuts - I'll soon be back at 100%. Thanks for the support."
The Montreal mixed martial artist confirmed in a text to The Canadian Press that it is not the same knee that required reconstructive surgery in December 2011.
"I'm OK," he said.
St-Pierre vacated his title in December saying he needed time away from the sport. But he kept training.
The 32-year-old fighter has said he plans to return to MMA but has not provided a timeline.
GSP has had his share of injuries.
In the fall of 2011, he sustained a minor left knee problem and pulled hamstring. He believes that led to overcompensating with his right leg when he returned to training. An attempted takedown during a wrestling drill led to a torn anterior cruciate ligament and a small tear to his internal miniscus.
That operation was done by Neal ElAttrache, the surgeon who looked after NFL star Tom Brady's knee in 2009.
"My knee feels like it never happened ... It's very strong," St-Pierre said later.
The Canadian returned in November 2012 to win a decision over Carlos (The Natural Born Killer) Condit at UFC 154, the then-champion's first fight in some 18 months.
St-Pierre (25-2) went on to beat Nick Diaz and Johny (Bigg Rigg) Hendricks, in a controversial split decision at UFC 167 last November, before opting to step away from the sport. He cited personal issues, without detailing them.
Hendricks won the vacant 170-pound title at UFC 171 earlier this month with a unanimous decision over (Ruthless) Robbie Lawler.
St-Pierre had to delay his first scheduled title defence back in 2007 due to sprained posterior cruciate and medial collateral ligaments. Surgery was not required then. And a 2006 fight was called off due to a groin problem.
He also had a layoff in 2009 after tearing his adductor muscle in three places in a UFC 100 win over Thiago Alves.