Former UFC title-challenger Chael Sonnen believes that Conor McGregor has made a huge mistake in clashing with the UFC. The featherweight champ sent a message out through his Twitter account earlier this week saying he was retiring.

UFC president Dana White went on to say that McGregor announced that after he refused to leave his training camp in Iceland to come to the U.S. and take part in a media tour to promote his UFC 200 main event against Nate Diaz. After that supposed refusal, White says he pulled McGregor from the match up and card.

While chatting with fans on Facebook Live, Sonnen warned the Irishman that UFC brass are Las Vegas high-rollers who are not to be trifled with. "I don't know if he wants to be done. This was a negotiation tool. But he called the bluff of the wrong guys," Sonnen said.

More from FoxSports

"These are gamblers man, there are rules in Vegas...Anytime you go into a negotiation and you call someone's bluff, man you had better mean it because this is what can happen."

Sonnen explained that the UFC had already invested a lot into promoting UFC 200 with McGregor and Diaz at the helm. According to Sonnen, White doesn't backtrack once he's dug in his heels.

"[McGregor] was sitting on top of the bill and this was done. The commercials are out. There's a lot of money that's already spent. There's a lot of billboards that are already up," he continued.

"I've known Dana since 2005. He's not putting a patch in this boat. Conor could call him right now, he's not patching up UFC 200."

Sonnen then turned his attention to who could possibly step-in for McGregor and face Diaz. In his mind, the UFC is going after one big name.

"Who's a good replacement for Conor? I guarantee you Georges St.-Pierre's phone is blowing up right now and he's getting a big offer," he said.

"That's the guy they're gonna go after."