Frank MirAccording to multiple reports, Frank Mir has sustained an injury in training that will force him out of his heavyweight title unification bout at UFC 98. What the exact injury is at this point though is a little unclear. Sam Caplan is reporting Mir suffered a back injury, while MMA Weekly is reporting he suffered a knee injury, and subsequently underwent minor surgery to repair it. reported that Mir suffered a back injury that has kept him from training recently and caused his removal from the UFC 98 main event bout.

Multiple sources, however, indicated that it is a knee injury that has precluded Mir from training. They also said that he recently underwent surgery to repair the knee, which will sideline him for the next four to six weeks to allow the knee to sufficiently heal.

It’s also unknown if a replacement will be found for Mir, or if the UFC will simply pull Lesnar from the card as well, and reschedule the bout when Mir is healthy, although, MMA Mania seems to think it’s the latter.

Mir will require time to heal after recently undergoing minor knee surgery to repair the damage. He is expected to make a full recovery. There is no timetable for a return; however, the good news is that it could be as soon as this summer.

Therefore, the highly anticipated heavyweight title unification match appears to be temporarily on hold — not canceled — for now.

Well, this just sucks. Definitely a bummer for what was one of the most anticipated fights of the summer. Hopefully, Mir makes a quick recovery and the bout is rescheduled for sometime later in the summer. We’ll keep you updated.

[UPDATE 3/6/2009 8:21PM ET] – The fight may still be on. Kevin Iole questioned Dana White following the UFC 96 weigh-ins today about the reports, and basically said he hasn’t heard anything.

UFC president Dana White said after the weigh-in for UFC 96 at the Nationwide Arena that he knew nothing of an injury by Mir. Mir and manager Dean Albrecht did not return messages.

“I don’t know anything about it, so I honestly couldn’t tell you anything about it,” White said of Mir’s injury and the report that the fight was off. “I’m not too worried about it now. If that were the situation, I’d know about it. I honestly don’t know right now. I haven’t talked to Frank and I haven’t talked to Lesnar and if that’s the situation, I’m not going to make any statements until I talk to everybody.”

But a source in Las Vegas close to Mir said his knee began swelling excessively last week after a workout. After an examination, Mir had arthroscopic surgery to “clean up” the knee.

Iole mentioned UFC 100 as a potential backup plan should Mir be unable to go on May 23.

[UPDATE 3/7/2009 1:51AM ET] – It looks like it was definitely a knee injury, not Mir’s back. Bloody Elbow found this interview with Mir at the Arnold Classic saying he recently had his knee scoped and hopes the fight gets moved into the summer.