The Ultimate Fighting Championship rumour mill is churning with talk of who the coaches will be for season 13 of “The Ultimate Fighter” reality television program. Many are speculating that the coaches will be Chael Sonnen on one side and Wanderlei Silva on the other.

Silva and Sonnen had a run-in a few months ago on their way to promote a UFC event. The two were travelling in a van along with Jennifer Wenk, the UFC’s public relations director when Silva called Sonnen out for some remarks he made leading up to his August 7, 2010 bout with Anderson Silva.

"I'm thinking. You sell the fight, you make a promotion, it's good, but you need to be careful talking about some things, like Brazil. You're talking bad things about Brazil," Silva said. "You don't know Brazil. When there is something you don't know, you need to respect that thing."

"Sure. That's not totally true," Sonnen responded. "I've been to Brazil, actually."

"No, no, you've been to Brazil, but I am Brazilian. Like you've been talking about the Nogueira brothers. These guys are the history of the sport; we need to respect these guys. You challenging him is okay. You know. One to one, you know? The promotion is good, but you need to respect some things," expressed Silva. "These guys need respect; and the country, you know? We need to have a good conduct about that. Okay? Don't do that anymore, because that's danger, no?"

"Sure, " Sonnen answered.

"In Brazil we have a saying: 'You have respect, you don't lose your teeth.' In Brazil we say that," Silva told Sonnen. "Give respect, because we don't know about the future, no?"

"Sure. Thank you," Sonnen responded.

Sonnen was awfully quiet during the face-to-face conversation with Silva, but afterward, according to Fighters Only, he publicly referred to Silva as “someone who used to be a fighter.”

When it was revealed that he had tested positive for having performance-enhancing drugs in his system for his bout with Anderson Silva, Sonnen went quite for a long period of time. He broke his silence last week in an interview with Inside MMA and since then he has taken to his twitter feed to renew his rivalry with Wanderlei.

Sonnen recently posted, "Wand, you might as well fill out your own toe tag. Where is says "Cause of death," just write, "I pissed off a Gangster.”

Silva then replied, “Sonnan you start tolk about me, becarful or you go need call to your dentista"

Sonnen has shown himself to be a master at self-promotion, so I would be very surprised if the jabs he is throwing at Silva are not based on something more than a dislike for the man.

UFC president Dana White was recently asked if Sonnen could coach “TUF.” White responded, “He could coach ‘The Ultimate Fighter,’ absolutely.”

Filming for season 13 of “The Ultimate Fighter” begins in January and MMAJunkie reports that Sonnen’s suspension for the positive drug test would not preclude him from coaching.

Sonnen’s six-month suspension will allow him to fight in March 2011.

Silva, rehabbing from knee surgery, is looking for a return to the Octagon in February or March.

In short, something seems to be brewing here, so stay tuned.