At this time, it is unknown how long Koscheck will be out for. Thiago, meanwhile, will remain on the card, however, the UFC has yet to sign a replacement to fight the Brazilian.
Thiago defeated Koscheck in a stunning upset at UFC 95 last February via first-round TKO in the Brazilian's Octagon debut. Since then, Thiago has gone 1-1 in the UFC, losing to Koscheck's teammate, Jon Fitch, at UFC 100 and beating Jacob Volkmann UFC 106 in November.
Meanwhile, Koscheck was also victorious at UFC 106 against Anthony Johnson. The American Kickboxing Academy product also picked up a win over Frank Trigg at UFC 103 since the loss to Thiago.
Update: Koscheck has confirmed the news via his Twitter account:
It's all good & I'll get my body rested & back to the top real soon. Keep checking my Twitter & I'll post news on my recovery."
Below is a look at the updated UFC 109: Relentless card:
Mark Coleman vs. Randy Couture
Paulo Thiago vs. TBD
Nate Marquardt vs. Chael Sonnen
Demian Maia vs. Dan Miller
Matt Serra vs. Frank Trigg
Justin Buchholz vs. Mac Danzig
Melvin Guillard vs. Ronnys Torres
Rob Emerson vs. Phillipe Nover
Brian Stann vs. Phil Davis
Tim Hague vs. Chris Tuchscherer
Rolles Gracie vs. Mostapha Al Turk