What happens when you put an undefeated all-time great boxer in the ring against an MMA champion with zero pro boxing experience? No one knows, actually. But we’re about to find out.

The Conor McGregor vs. Floyd Mayweather superfight goes down this weekend, and it’s equal parts sport and spectacle. Some may even argue that it’s 100 percent spectacle, and one group that isn’t a fan of the hype is the Association of Ringside Physicians (ARP). The ARP is a collection of more than 100 doctors who attend combat sports events in case an athlete suffers any sort of serious injury.

On Thursday night, the ARP publicly announced their disapproval of the Nevada State Athletic Commission’s decision to sanction the McGregor vs. Mayweather fight, claiming that McGregor doesn’t stand a chance and could end up seriously hurt as a result.

“We were very surprised this bout was even sanctioned and was going to be permitted to carry on,” Larry Lovelace, a doctor and president of the association said, according to Joe Depaolo of the New York Times. “The thing I really fear, truly fear, is that somebody’s going to get really hurt in this upcoming fight.”

We’re sure you’ve heard by now, but Mayweather is a perfect 49-0 in his boxing career and generally accepted as one of the sports’ all-time greatest. McGregor may also be in the fight game as a multiple division UFC champion, but that’s a vastly different skill set than the sweet science. He has never boxed professionally in any capacity.

Former boxing referee Richard Steele echoed the ARP’s comments in the same New York Times piece:

“Here’s a guy from one sport, challenging the world’s best in his own sport. I really don’t know how it’s going to work,” Steele said. “He can’t kick. He can’t elbow. He can’t do nothing. Nothing that he’s used to doing that makes him a great MMA fighter.”

The fight goes down Saturday night on pay-per-view.