Sherdog has the scoop:

Lembo, a former wrestler, said there wasn’t much support to allow knees to the head of a grounded opponent, a staple of the Pride Fighting Championships. He said the technique generates too much force, has too much potential to inflict serious damage and could produce ugly scenes that would boost the stigma of brutality that MMA has battled since day one.

"Hardcore fans want knees to head on the ground, and I can tell you it’s not going to happen," Lembo said. "One of main reasons it’s not going to happen is because the industry itself doesn’t want it. It’s not only the doctors who are concerned about it."

Pat Miletich agrees. The UFC’s first welterweight champion, who returns to fighting on Dec. 13 for Adrenaline MMA, was one of several fighters to lend his thoughts to the ABC.

"I don’t see a need for knees to the head on the ground," Miletich said. "That’s something that has potential for some serious fractures. Being concerned for athletes’ overall longevity and health, I don’t think that’s something that’s needed."

I tend to think there's more play here with the rule than officials are letting on. I do believe knees to the head of a prostrate opponent can be damaging past the tipping point, but I don't feel that way about an opponent who is simply down by three points of contact. In other words, the knees Kevin Randleman drove into the head of Kenichi Yamamoto are far less troublesome than a knee to the head of a fighter who gets a double leg shot stuffed and is stalling. It might be too difficult to clearly enforce a rule where a fighter can knee the head of a downed opponent with three points as opposed to four points of contact, but it's worth admitting not all knees to the head of a downed opponent are created equal.