UFC welterweight champion Georges St-Pierre blew out his anterior cruciate ligament (ACL) in his knee and is forced to pull out of his championship bout against Nick Diaz at UFC 143 on Feb. 4, 2012, in Las Vegas.

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

St-Pierre is expected to be out of action for approximately 10 months.  This follows the champ pulling out of his UFC 137 bout against Condit in October when he sprained his medial collateral ligament (MCL).

Josh Koscheck was scheduled to meet Condit at UFC 143, but no replacement has been announced for the American Kickboxing Academy fighter as of yet.

The drama surrounding Diaz vs. St-Pierre has been ongoing since July when the Stockton, California native missed a press conference and Condit was brought in to face the Canadian.  Comments were made from Cesar Gracie, Diaz’s coach, prior to UFC 137 that GSP appeared to be fine after claiming an injured MCL.