George St. Pierre will not be fighting Nick Diaz at UFC 143 as an ACL tear sidelines "Rush". Carlos Condit set to fight Diaz for the interim welterweight title according to ufc.com.

"GSP blown acl will be out for 10 mos. Now (Carlos) Condit vs (Nick) Diaz for the interim welterweight title on Feb 4th in Las Vegas!!" Dana White, UFC president, said.

According to St. Pierre's personal friend and doctor, Sebastian Simard, St. Pierre suffered his injury during training when a takedown defense led to hyperextension of his right knee. A following MRI exam revealed a complete tear of his ACL as well as a small tear of his internal meniscus. St. Pierre also had a MCL sprain earlier this year, in mid-October, that forced him out of UFC 137's fight with Condit.

Dr. Simard further stated that St. Pierre would undergo surgery for ACL reconstruction with an estimated recovery time ranging from six to nine months.

"I believe there is only one person to blame after what happened, and it's myself. I'm the kind of guy that sometimes I experience pain, and I can go through it. That's what I do all the time. But I learned a big lesson in my life...I'll be back on top, and mark my word, I will be champion before the end of 2012," St. Pierre said.

In light of this new development, Condit will now fight Diaz at UFC 143 for the interim welterweight title. It has been a wild few months for Condit to say the least according to bloodyelbow.com.

"So...another change of opponents. It's been kind of a crazy ride the last couple months but you know, just gotta kinda roll with it," Condit said.

Condit's title contention has come full circle. He was the original challenger to St. Pierre's belt at UFC 137 but the fight was delayed and Condit was eventually bumped in favor of Diaz. And now with St. Pierre sidelined for the near future, Condit is once again ready to step up to the challenge.

"I've been wanting to step into the octagon with Nick Diaz for a really long time. Great fighter. Great skill set. I think that we're really going to put on a good show for the fans...I will be the UFC interim champion. And then when Georges gets better I will be the undisputed UFC champion," Condit said.

Diaz's longtime coach, Cesar Gracie, also has high expectations for the upcoming UFC 143 matchup. As Gracie points out, Condit possesses superior striking skills when compared to St. Pierre that should make for an "intriguing" fight according to mmamania.com.

"He (Condit) kicks better, he throws better punches, he is taller. From a fans perspective, and I am a fan myself, it's actually a more intriguing matchup...I really think this is going to be a rock em' sock em' fight," Gracie said.

Diaz is on an eleven fight win streak and last battered BJ Penn to a unanimous decision at UFC 137. Condit stopped previously unbeaten Dong Hyun Kim in the first round at UFC 132 in his previous fight. Both men have 13 TKO/KO stoppages to their credit.

"I think it should be the championship fight because since the Jake Shields fight, by the time GSP fights again it's going to be about two years. A champion being out for a couple years, my idea is that they should actually strip him," Gracie said.

For the time being it is...