Tito Ortiz posted a message on his official Twitter account Tuesday morning stating that UFC 106 opponent Mark Coleman has withdrawn from their bout.

After saying it was too bad Coleman “sissies out,” Ortiz added, “I'm kicking someone's ass on Nov 21st!”

Multiple sites have confirmed that Coleman is out of the event, which is scheduled for the Mandalay Bay Events Center in Las Vegas and headlined by the Brock Lesnar-Shane Carwin heavyweight title fight.

Coleman could not confirm his withdrawal from the bout as of Tuesday morning.

“Yes, I hurt my knee and I’m very disappointed,” Coleman told Sherdog.com, “but I’m still waiting to hear from the UFC, so I have no comment until then.”

Coleman said he would address Ortiz’s comments at a later time.

If Ortiz remains on the card as he suggested, he will be fighting in the UFC for the first time since his May 2008 loss to Lyoto Machida. Coleman, who has fought Fedor Emelianenko twice, is 1-1 since returning to the UFC in January 2009.

This article was updated at 2:07 p.m. EST to include information from Mark Coleman.