“Leatherheads” could have been a great movie. Think “Slap Shot” except with football, set in the ’20s and starring George Clooney. Sounds great, right?

But “Leatherheads,” despite some fun moments, didn’t quite work for a few reasons.

The plot certainly wasn’t a problem. “Leatherheads” tells the story of Dodge Connelly (Clooney), an aging football player who, back in 1925, is trying to legitimize professional football and save his team – the Duluth Bulldogs – from going bankrupt.

To do this he enlists the help of Carter Rutherford (John Krasinski), a war-hero football star from Princeton. But when Lexi Littleton (Renee Zellweger), an ambitious reporter from the Chicago Tribune, shows up to sniff out the lies in Rutherford’s war record, things go haywire as she finds herself in a love triangle with both football stars.

Potentially juicy stuff, but it doesn’t quite hold together.

One reason is that the pacing lags behind the plot. The film is styled in many ways after the screwball comedies of Old Hollywood, which was a smart choice for Clooney. He knows he does the industry’s best Cary Grant.

But Old Hollywood’s humor was a race to the finish line. Not a moment was wasted that could be plugged up with a zinger and all possible fat was trimmed. Too often where “Leatherheads” should be briskly hopping along in this time-honored style, the film instead drags its feet.

Perhaps the biggest problem in “Leatherheads”, however, is Zellweger’s role in it all. For some reason, she just doesn’t seem to fit into the movie. I’m not sure if it was her dialogue or her acting, but she does not come off as the sassy, sexy, proto-feminist that the story called for.

I can see why Zellweger was cast in this role (“Chicago” was, after all, a pretty popular movie), but casting her as a spunky, prohibition-era vamp just didn’t work this time. As a result, the romance came off as flat as a week-old soda. The tension never sizzled. Sparks never flew.

Despite all of this, there is much to enjoy in “Leatherheads.” The muddy fields and smoky speakeasies are photographed beautifully and Clooney is great at coaxing the little moments out of this film: the giant high school player waiting at the railway station; the sloppy drunk sports reporter. Randy Newman, who wrote the film’s lovely and nostalgic score, even makes a cameo as a piano player during one of the film’s many bar fights.

But “Leatherheads” is really at its best when punches are flying. As smooth as Clooney is, he is really a master of physical comedy. The man knows how to take a prat fall, and he takes more than a few in this film. The team he assembles has a great cartoonish quality about them, and whenever they’re on the field (or in the bars) the film moves forward with substantial gusto.

Underneath all the mud, this is a film about guys who love football, and loved it even when no one else cared. A little more focus on that, and “Leatherheads” really could have been a classic.

Kevin Corcoran can be reached at [email protected].