These days, the UFC encourages fighters to air their matchmaking wishes in a public forum. Provided it's not too wacky a request, callouts can help gauge interest in future bouts.

But that's one offer Matt Brown is going to turn down.  

"I sort of called out one person in my entire career, and that was Renzo," he told MMAjunkie.com Radio. "I wished I never did it; I pretty much got barred from their team."