Sylvester Stallone may pummel Julia Roberts

Not physically, of course. But it could happen this weekend at the box-office.

Stallone's old-school action-flick “The Expendables” is poised to become the top-grossing film over the coming weekend, beating Robert's foodie travelogue “Eat Pray Love,” according to BoxOffice.com. The site predicts that Stallone's crew of grizzled butt-kickers (including Dolph Lundgren, Steve Austin and Mickey Rourke) will pull in $30 million, while “Eat Pray Love” will take second place with $28 million.

BLOG: Choosing between "Eat Pray Love" and "The Expendables"

PHOTOS: "Eat Pray Love" | "The Expendables"

Late last month, Phil Contrino, editor of BoxOffice.com, had predicted a mere $19 million opening for “The Expendables,” but the film has clearly been gaining momentum as it nears Friday's release date. A recent poll by ticket-seller Fandango.com showed that 10% of moviegoers are planning to see “The Expendables.” (Side note: More than a third of those are female.)

How did Roberts, arguably the biggest star of her generation, potentially lose the edge to Stallone, whose career peaked in the 1980s?

For starters, Roberts hasn't truly toplined a hit film in a decade; “Erin Brockovich” came out in 2000. Even her last “Ocean's” film came out six years ago. It's possible that viewers have grown accustomed to seeing her as a co-star or a supporting player in disappointing films like “Duplicity” and throw-aways like “Valentine's Day.”

Stallone, meantime, has the underdog's advantage. He's underexposed, fondly remembered by older moviegoers and considered a legend by younger ones. “The Expendables” also arrives at a time when action films – and their muscular, alpha-male stars – are in short supply.

If “The Expendables” performs as expected, here's another look into the future: more action films.