Strikeforce heavyweight champion Alistair Overeem has been a fighter under the Zuffa banner for only a few short months now, but already the relationship has become a bit strained.Overeem told Ariel Helwani on Monday's edition of The MMA Hour that he has not agreed to the proposed Sept. 10 date for the semifinal round of the Strikeforce heavyweight Grand Prix, and his opposition is causing some tension with his new employer."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."Originally, Overeem said, he agreed on an October return to the cage to face Antonio "Bigfoot" Silva in the next round of the tournament. He claimed he needed that time to recover from his last fight -- a three-rounder with Fabricio Werdum in the quarterfinals, which he said he went into with a broken toe -- as well as to properly prepare for Silva.Recently he was informed that Strikeforce was targeting the date in early September, which Overeem deemed "too short notice," and rejected. Then the backlash from his new employers began, he said."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."Overeem said he's let his management handle all the negotiations and has not spoken directly with anyone at Strikeforce or Zuffa on the subject because he has a "too short temper to deal with people who can be disrespectful."This is the first negative experience he's had with the new Strikeforce owners, Overeem said, but it's one that seems as though it could derail the relationship early on."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.Overeem added that he was unsure how seriously to take threats that he could be cut from the tournament, but insisted he wouldn't be pressured into taking a fight before he felt adequately prepared."The fights that I've lost -- I'm not the guy going for excuses -- I blame myself. That is where this decision is coming from. I don't want to blame myself. ...What I do now is I [do] my homework, I make sure everything is perfect, and then I fight. With that formula I've had some great results in the last four years, and I'm not prepared to throw that all away because people pressure me."If he is dropped from the tournament, Overeem said, he still plans to fight in October. He noted that his Strikeforce contract allows him to fight in other promotions, so he's already informed his management to make sure that he has a fight lined up -- either in MMA or even potentially in K-1 -- for October."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."As for reports that he'd be interested in a boxing match with one of the Klitschko brothers , Overeem acknowledged that he might need a few warm-up bouts first -- he currently has zero pro boxing matches to his credit -- but added that his K-1 experiences had only improved his striking skills for MMA, so perhaps some boxing experience would do the same."Boxing is a new challenge," he said. "Why not?"In fact, the only fight he doesn't seem interested in is one on September 10. While some fighters might need to capitulate to promoter demands due to the state of their careers, Overeem said, he isn't one of them. He's still the Strikeforce heavyweight champion, and he isn't going to be rushed."I'm a fighter who likes to fight," said Overeem. "I love to be very active. I'm going to fight [in] October regardless. If it's not going to be for Strikeforce, then I'll fight somewhere else."