The UFC’s second trip to Montreal is in jeopardy following a decision by the Quebec Boxing Commission this week to adhere to regulations that prohibit elbow and knee strikes and other standard MMA moves.

Sportsnet.ca was the first to report on the story on Thursday.

Nearly 13,000 tickets have been sold for UFC 97 “Redemption,” scheduled to take place at the Bell Centre in Montreal on April 18, according to Marc Ratner, Vice President of Regulatory Affairs for the UFC. The show, which pits middleweight champion Anderson Silva against jiu-jitsu ace Thales Leites, may face tough choices in the coming days though.

The UFC broke attendance and box office records with its first event on Canadian soil 10 months ago, though that show was regulated under rules more akin to the unified rules of combat recognized throughout North America.

From 2000-2008, the Universal Combat Challenge, later renamed TKO, held 44 of its 46 events in Quebec under similar regulations as well.

But now Québécois officials are saying the province does not have the latitude to allow those or any other set of regulations outside of the ones they already have in place.

“We had a tolerance for the application of the rules in the past,” Réjean Thériault, director of communications for the combat sports division of the Governing Body of Alcohol, Races and Games of Quebec (RACJ), which oversees the commission, told Shedog.com on Thursday. “We learned today that we had a place for tolerance and we didn’t know. Now we know the rules under which to live. We informed all the promoters last week that they must now respect the rules of Quebec.”

Those rules regulate boxing, kickboxing and “mixed boxing,” which is described as a combination of boxing, kickboxing, wrestling and jiu-jitsu. Along with the prohibition of elbow and knee strikes both standing and grounded, the regulations also state that a referee will utilize a standing count to check on a fighter that has been knocked down.

The Octagon might also face downsizing to comply with the requirements, said Thériault.

Ratner, who has been in close contact with both the RACJ and commission in the last few days, said he believes the genesis for the sudden turn-around came from the near-riot that occurred last Friday at a Strikebox/Titans Fighting event in Montreal.

That event, promoted by former TKO president Stephan Patry, aimed to utilize MMA striking rules, but negated the ground aspect of the sport. However, the commission advised Patry that the proposed rule changes would not be allowed, and that the show would follow MMA regulations instead.

A private agreement amongst a majority of the fighters to keep the bouts standing was followed until the main event, when British brawler James Thompson took down Steve Bosse and began to ground-and-pound the Canadian hockey enforcer. The crowd of nearly 1,200 spectators erupted in disapproval, throwing chairs and beer cans. The commission called the contest, while the fighters had to be escorted out of the cage by security.

Though Thériault acknowledges that the Strikebox/Titans fiasco played a role in what appears to be a sudden adherence to the rules on hand, he said the decision has already been in the works for some time.

“[The Strikebox scenario] was an important part of getting us to this point, but Richard Renaud [Director of the Division of Combat Sports in the RACJ], who is replacing Mario LaTraverse, has been working with the President of the RACJ, Denis Racicot to change the sport, and noted that we had tolerated the [past] rules,” Thériault said.

Ratner believes LaTraverse’s retirement from the commission has also played a role in the recent events, but sees a positive outcome on the horizon.

“We're aware of the situation and working with [the RACJ and the Quebec Boxing Commission] to resolve the situation,” Ratner told Sherdog.com on Thursday. “I'm confident that this will all work out.”

While Ratner said discussions regarding the rules would continue into next week, Thériault emphasized that the RACJ was neither making any drastic changes nor trying to run the UFC out of town.

“We’re not following any new rules,” he said. “We’re following the rules that are in place.”

Loretta Hunt contributed to this report.