Melvin Guillard only fought twice for World Series of Fighting, but bitter feelings from the relationship's bizarre end still linger.

"I don't think it ended poorly. I just think Melvin, he's out of his mind," WSOF executive vice president Abdel-Aziz said Monday on The MMA Hour. "I don't really care about Melvin. He's a UFC reject. He's a WSOF reject. Now he's headlining Bellator's main event. Like, the guy was talking so much s**t. When he left the UFC, he was talking s**t about the UFC. When he left World Series of Fighting, he was talking s**t about World Series of Fighting. When he's going to get cut from Bellator, he's going to talk about Bellator."

Guillard makes his Bellator debut this Friday in the main event of Bellator 141. The bout will be Guillard's first since the 32-year-old and WSOF parted ways following a tumultuous run inside the organization, one which saw Guillard badly miss weight for both of his fights and publicly criticize WSOF as a "B-league" promotion.

Guillard initially inked his deal with WSOF in April 2014 following the abrupt end to his 22-fight stint in the UFC. Despite coming in overweight for his WSOF debut, Guillard was awarded a title shot against lightweight champion Justin Gaethje for his sophomore effort. Tensions between Guillard and WSOF officials escalated when the fighter and Abdel-Aziz aired their grievances during a memorable media conference call, and things fell apart soon after.

Guillard showed up to the Gaethje fight four pounds overweight, rendering it a non-title bout. He was then pulled from his next bout after failing to provide medicals in a timely fashion and refusing to do media to promote his fight, aside from an interview with Submission Radio in which Guillard slammed the organization and its executives. Guillard ultimately asked for and received a release from his WSOF contract, leaving Abdel-Aziz frustrated by the very public manner in which way the situation played out.

"People know what Melvin is," Abdel-Aziz said. "And honestly, I'm upset with Melvin. Because after he asked for his release and [manager] Malki [Kawa] asked me, and we gave him his release and he sent me a text message saying ‘thank you, I really appreciate it,' the whole thing is he's going on the internet and talking about WSOF is s**t and UFC is s**t. He's s**t. Like, Melvin sucks. Honestly, I think he's an explosive, athletic guy, he's getting older -- it's not working for him.

"Listen, Melvin, we had some sparring sessions in the gym at Greg Jackson's, and I beat Melvin every time. Melvin is never going to be a world champion. Melvin is going to be a world champion of one thing: he taps. That's what Melvin does. That what he does, he's the world champion of tapping.

"All you've got to do is just match him up with a wrestler. He's going to take him down and finish him. That's how I finished him in the gym and Greg Jackson was a witness of that."

Abdel-Aziz pointed to a similar labor dispute he had with former WSOF title challenger Josh Burkman. Despite their differences, Burkman was granted his WSOF release and has since fought three times in the UFC. Abdel-Aziz says he personally helped facilitate the move with UFC President Dana White, simply because of the professionalism Burkman displayed throughout the situation -- professionalism he feels Guillard did not share.

"It seems like f**king everybody is leaving a promotion now and talking s**t about the other promotion," Abdel-Aziz said.

"I didn't have to release Melvin. Melvin, if he was still with World Series of Fighting, would probably be fighting on the undercard somehow. Now he's headlining a main event. But you know what, it's good for him. But I'm not worried about it. Even his coaches, his own coaches, they were asking me, ‘why are you not cutting this guy? He doesn't deserve to be at World Series of Fighting.' He's a guy who burned a lot of bridges, but listen, we have a lot of great things going on at World Series of Fighting. The last thing I want to worry about is Melvin."