Strikeforce officially announced their long-rumored Sept. 10 card today. Along with the announcement came confirmation of many rumored match-ups including Ronaldo “Jacare” Souza vs. Luke Rockhold, King Mo Lawal vs. Roger Gracie and Josh Thomson vs. Maximo Blanco, plus the addition of Evangelista “Cyborg” Santos vs. Jordan Mein.

What wasn’t confirmed however was the semi-final bouts of the Strikeforce Heavyweight Grand Prix. It was reported last week that Strikeforce’s Sept. 10 card would feature Alistair Overeem vs. Antonio Silva and Josh Barnett vs. Sergei Kharitonov, however at least one of the semi-finalists doesn’t approve. On The MMA Hour with Ariel Helwani today, Alistair Overeem stated that Sept. 10 is too soon and he will not agree to that date.

“That is not going to take place,” Overeem told Helwani. “Stikeforce has requested me to accept the fight for Sept. 10, to agree on that, but I have not agreed on it and I also had some emails, some questions asked, is the fight confirmed? No, the fight is not confirmed. I do not confirm it and I will not confirm it.”

In the past, Strikeforce probably would have caved in and pushed the semi-finals to a different date to accommodate their heavyweight champ, however Overeem is finding the new Zuffa-owned Strikeforce to be much more difficult to deal with. Overeem claims Zuffa is playing hardball with him and threatening to pull him from the tournament if he doesn’t agree to the Sept. 10 date.

“What’s going to happen next, I don’t know. I’ve had some threats of cutting me out of the tournament if I don’t participate. I don’t know if they’re going to do it. Personally, I don’t like to be threatened. If people start talking like that then…be my guest, but then I’m really not going to sing to their tune.”

“For them to unilaterally declare, okay, [September 10] is going to be the second round, which I never agreed on, and then threaten me if I don’t want it, it…doesn’t really show a lot of respect,” he said.

As Overeem explains, respect is important to him and he has other options if Strikeforce isn’t going to give it to him.

“The thing is, there’s other promotions. There’s other stuff I can do. K-1’s going to come back. There’s some good reports on that. There’s some other promotions in the world that would love to have me fight. So for me, the respect thing is definitely a factor and it’s definitely important.”

Another option Overeem has been touting in the past week is professional boxing. In an interview with last week, Overeem revealed that he’s interested in boxing Vitali Klitschko. He followed that up with a statement to MMA Fighting today reasserting his desire to fight one of boxing’s heavyweight champs.

“I would love to fight one of the Klitschko brothers. I think it will be great to see how one combat sport world champion will do against another world champion. There are many reasons to challenge him: boxing has been the No. 1 combat sport for years and MMA is growing and closing the gap with boxing. I would like to bring both worlds together by being the first MMA and K-1 champion to cross over into boxing.

There are many boxers that have competed in K-1 or MMA but vice versa, it’s something that has not been done yet, so why not? I always like to challenge myself. I like to try new things. I know that a lot of people will call me crazy and will think that a boxing champion will have the full advantage. I’m fully aware that I’m the underdog going into the fight, but that was the same thing when I fought K-1 champion Badr Hari. People thought I was foolish to even try to fight such a name as an MMA fighter, but I took the chance and I defeated him. Two years later, I was crowned the K-1 champion.

If you don’t try, then you will never know. Nobody has ever seen two combat champions fight in a boxing match so I think that I have the credentials to try. My current contract allows me to fight another sport so now I can do it. The last reason I can think of is that I know that Klitschko doesn’t have many challenges in boxing anymore. The heavyweight division isn’t very interesting anymore, so maybe I can give some color to the division and make for an exciting fight. If I look at the David Haye vs Wladimir Klitschko fight, I was a little disappointed. Klitschko was much better. No disrespect to Haye, but I truly believe I can make a more exciting fight, win or lose. As a true fan of MMA, I always liked the concept to see different combat sports fighting it out, so I’m going to make a bold statement and challenge Klitschko under his rules and his terms. I’m not in any way trying to disrespect him by challenging him, but he and I know this fight will not go to a decision!

It’s up to the fans’ response. I only want to fight him if there is support in both boxing and MMA communities. If the fans want it, I’m in!”

Note that Overeem mentions his contract allows him to fight in other sports, much like Nick Diaz’s did, and according to Scott Coker, it was Nick’s boxing provision that ultimately secured him the deal with the UFC.

So I ask you: Is it merely just a coincidence that Overeem suddenly wants to box while getting strong-armed by Strikeforce or is this an attempt to gain some leverage over Zuffa brass when there’s little to be had?

In other words, is Alistair Overeem trying to pull a Nick Diaz and get the upper hand?

Image via Esther Lin for Strikeforce/Showtime