EA Sports MMA won't release until September 2010, according to an article from a European mixed martial arts publication posted in the EA Sports forums. There is no online version of this article.
So, given the audit trail for that rumour, let's take it with a block of salt. And I've gone ahead and emailed EA Sports MMA's publicity contact to let them know their name's in someone else's mouth. But if that's a fact, wow. UFC 2010 Undisputed, which just got a glowing debut at Saturday's Spike Video Game Awards, is said to be on track for May 25 thanks to the latest GameStop circular. I would half expect EA Sports MMA would have to release much closer to that date than four months, if not before it.
Pasta Padre wisely points out that such a release would put it smack dab in the middle of EA Sports' high season for releases: Madden in August, NHL 11 in September, NBA Live and FIFA in October. It runs the risk of being well overshadowed by the established franchises.
The source on the rumour is the UK-based Fighting Spirit magazine, the only European publication invited to a recent EA Sports MMA press conference, so it has a track record of covering the game. The magazine went on to describe several features about the gameplay, including Unified Rules, Pride Style Rules, foot stomps, fighting on the cage, and other details. So check out the post if you're interested in that.
Should EA Sports take a swing at this, I'll update it here. I've also emailed Fighting Spirit magazine to double-check their side of this.
Update: An EA Sports spokeswoman has told Kotaku "We have no comment on speculation or rumour at this point."