LAS VEGAS -- Nine million dollars is a great deal of money to be spent on a boxing canvas, but the "Planet Hollywood" ring on which Bernard Hopkins and Joe Calzaghe will fight Saturday night at Thomas & Mack Center here is a worthwhile investment to the company's founder, Robert Earl.

Earl, who in 2005 took over the Las Vegas hotel/casino once known as the Aladdin, says he was encouraged by business partner and "Rocky" star Sylvester Stallone to join the MGM Grand and Mandalay Bay as a destination for major boxing shows.

"Sly told me if you're going to be a player in this town, you have to be involved in boxing," Earl said earlier this year at a Los Angeles news conference featuring the fighters.

So, Earl negotiated with Calzaghe's English promoter Frank Warren and Golden Boy Promotions executive Richard Schaefer to create Saturday's "Battle of the Planet."

Impressed by the throng of Brits who came to Las Vegas to cheer on countryman Ricky Hatton in his December loss to Floyd Mayweather Jr., Earl reportedly originally paid $11 million for the site rights to lure Calzaghe from Wales. Promoters later refunded him $2 million due to slow ticket sales -- Calzaghe's popularity doesn't rival Hatton's.

Last month, veteran promoter Bob Arum of Top Rank predicted Earl's involvement in the sport would be "one and done." However, Arum now says a Planet Hollywood official has convinced him that Earl is legitimately "enthusiastic" about making boxing part of his hotel's appeal.

Planet Hollywood will back a light-heavyweight fight featuring Chris Byrd on May 16 at Las Vegas' Cox Pavilion, and the Ricardo Torres-Kendall Holt World Boxing Organization junior-welterweight title rematch, promoted by Arum's Top Rank company, will be at Planet Hollywood's 7,000-seat theater in early July.

Earl, who once presided over the Hard Rock enterprise, said he ultimately aspires to construct a larger "Planet Hollywood" arena.

Yet, more venue competition is in the future, with AEG scheduling summer groundbreaking for a 20,000 Las Vegas arena to open in 2010.

"Boxing is a staple of any arena in Vegas, and this state-of-the-art arena will be beyond even Staples Center," AEG spokesman Michael Roth said.

Golden Boy's Schaefer said even if Hopkins-Calzaghe ticket sales generate only $7 million to $8 million, Earl has accomplished "quite a coup with this big fight, getting his hotel public exposure and marketing value that is worth a substantial amount of money."

The boxers will earn $3 million apiece, said Nevada State Athletic Commission Executive Director Keith Kizer.

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In L.A., unbeaten light-middleweight Julio Cesar Chavez Jr. (35-0-1, 28 knockouts) will attend a news conference at the El Pueblo Monument at Olvera Street at noon Sunday to promote his April 26 bout in Mexico against Giuseppi Loriga (24-0-1).

The event will include Mexican and Italian music, with a public dance contest. The fighters will serve as judges.

lance.pugmire@latimes.com