Injury woes continue to create chaos for upcoming UFC cards and welterweight contender Josh Koscheck is the latest in a seemingly never-ending string of casualties. Koscheck suffered an undisclosed injury in training and has been forced to withdraw from his scheduled rematch with Paulo Thiago at UFC 109.

Thiago shockingly knocked Koscheck out in the first round of their initial meeting at UFC 95 and Koscheck had aimed to avenge the loss. Thiago will still compete at UFC 109 against an opponent to be named soon.

Koscheck (14-4-0) had made headlines prior to the first bout with Thiago when he bragged that he had no idea who Thiago was. Despite dominating nearly all of the brief fight, Koscheck was knocked out by an uppercut-hook combo from the unassuming Brazilian. Since then, Koscheck rebounded with a pair of stoppage victories over former title challenger Frank “Twinkle Toes” Trigg and fellow contender Anthony “Rumble” Johnson, and had petitioned UFC management to give him a title shot.

The nature of Koscheck’s injury was not disclosed and it is unknown when he will be able to return to competition. Previously stating his intentions to compete ten or more times in 2010, Koscheck may no longer be able to keep up such a schedule. He will likely need to win at least one more fight against a top contender before he will get another shot at UFC Welterweight Champion Georges “Rush” St. Pierre.

Thiago (12-1-0) has had mixed success since his shocking win over Koscheck. The talented Brazilian, who works in a specialised police task force when not competing in mixed martial arts, dropped a three-round affair to former title challenger Jon Fitch in July, but rebounded with a hard-fought decision win over Jacob “Christmas” Volkmann at UFC 106. A replacement opponent for Thiago will be announced soon.

UFC 109: “Relentless” takes place on February 6, 2010 at the Mandalay Bay Events Center in Las Vegas, Nevada. The event airs live on pay-per-view.