Las Vegas ? The Mirage hotel-casino lost one of its biggest money-making shows when a tiger nearly killed Roy Horn of “Siegfried and Roy.” Now the resort has to figure a way to plug an annual revenue hole estimated in the tens of millions of dollars.

MGM Mirage officials say it’s too early to say who will replace the legendary headliners — a mainstay at the Las Vegas Strip property since 1990.

The extent of Horn’s injuries hasn’t been revealed. The illusionist remained in critical condition Monday with a gaping wound to the neck. Doctors said Horn exhibited signs of improvement when he moved his feet and hands and gave the thumbs up sign late Sunday.

That’s the best news MGM Mirage executives have been able to offer since Horn was attacked by the 600-pound-plus white tiger on Friday night during a sold-out performance.

With the “Siegfried and Roy” show closed indefinitely, company executives will try to find a profitable replacement fast, but it won’t be easy. The duo put on what was arguably the most successful show in Las Vegas history, said John Mulkey, a Bear Stearns gambling analyst.

“It’s safe to say that acts like Siegfried and Roy don’t pop up overnight,” Mulkey said.

Wall Street was still deciding Monday what effect the show’s cancellation would have on The Mirage’s bottom line.

The show generated about $44 million in annual revenue and attracted nearly 400,000 people a year, according to UBS Investment Research in New York.

David Anders, a gambling analyst with Merrill Lynch, wrote Monday that The Mirage would lose about $5 million a year in profits.

Mulkey said the casino could fill the pair’s theater with bands or other acts that are easy to book. MGM Mirage spokesman Alan Feldman said the tigers, lions and other exotic animals that live at the casino’s Secret Garden attraction would remain on display.

Horn and longtime partner Siegfried Fischbacher have been a staple on the Las Vegas Strip for years, performing their magic show to sold-out crowds at The Mirage since 1990.

The illusionists, who put on one of the most well-known and expensive Las Vegas shows with their signature white tigers and lions, signed a lifetime contract with the resort in 2001.

The German-born pair perform six shows a week, 44 weeks per year and have been onstage in Las Vegas for more than 35 years. They have done about 5,700 shows since coming to The Mirage in 1990.