Football is a fall game, usually associated with brilliantly hued foliage, brisk weather and bulky sweaters.

But that simple fact made for a not-so-simple problem yesterday when filmmakers tried to shoot crowd scenes for a football movie called "The Replacements" at Baltimore's PSINet Stadium on a day when temperatures reached into the 90s.

"I brought my fur wrap and hat with fur trim, just like they told me," said Violet Johnson, 36, one of about 10,000 volunteer extras for the Warner Bros. film, loosely based on the 1987 NFL players' strike and the success of the Washington Redskins' undefeated fill-in squad.

"But, gracious, I can't imagine putting them on in this heat."

As a matter of fact, instead of wearing fall garb as requested by the producers, scores of people filled the sun-splashed stadium wearing only shorts, tank tops and even bathing suits to take part in a movie starring Gene Hackman and Keanu Reeves.

"I just want to know who is going to have the job of digitally taking out all of the people without shirts," said Rob West, 19, an engineering student at Catholic University whose fan makeup was melting from his face. "It sure doesn't look or feel like fall out there."

Not to worry, said Jeffrey Chernov, the film's executive producer, who said he didn't have the heart to press people about donning the heavier clothes.

"We'll figure something out," he said, noting that the movie includes a scene to be set in early fall. "At least it is not supposed to be the dead of winter."

Although the film is based loosely on the ragtag group of castoff players who were embraced briefly by Washington area fans, the NFL refused to let the Redskins trademarks be used, Chernov said.

Hapless and sometimes sloppy, the real replacement players had 24 days of glory and won all three games they played against St. Louis, New York and Dallas. After that, the real Redskins went on to win two playoff games before winning the Super Bowl against Denver.

Extras resurrected the mood and charm of those surprising old games yesterday during the filming.

"We want the scabs! We want the scabs! We want the scabs!" they crowed, waving helmet-shaped signs, big foam fingers and pompoms.

In the movie, Hackman, coach of the fictional Washington Sentinels, has one week to find replacements before a big Sunday game. His character is not unlike former Redskins coach Joe Gibbs, Chernov said.

"It is incredibly funny," said Dylan Sellers, one of the film's producers. "From convenience store workers to steel mill workers, these guys got a second chance at being great."

Reeves plays Shane "Footsteps" Falco, the quarterback who "runs a little scared" when he hears footsteps behind him, Sellers said.

Warner Bros. is scheduled to film again today. Anyone interested in playing a fan in the movie should go to Gate A of PSINet Stadium at 9 a.m. Extras are not paid, but they do have chances to win jerseys and footballs signed by the film's stars, as well as cash prizes, televisions and VCRs.

As for the fall garb? Bring it, Chernov said: "We'll play it by ear."

CAPTION: Thousands of volunteer extras cheer for a fictitious team during filming of the movie "The Replacements."