Who knew Jim Halpert could throw a ball like that?

Jim Halpert, known as actor John Krasinski by those not “Office”-obsessed, stars alongside George Clooney and Renee Zellweger in “Leatherheads,” directed by Clooney himself. Together, the seasoned expert, the grown-up blongenue and the boy wonder from Brown carry a ’20s-era football flick in a pretty and inoffensive manner, but fumble the ball before they reach the end zone.

“Leatherheads” chronicles the evolution of professional football into the form with which we, Bud Light-drinking Americans, are familiar. The year is 1925 and the war is over, the boys are back home and ready to play some ball. Unfortunately, there is a shortage of balls — and money and legitimacy — outside the gates of schools like Yale and Princeton. Carter Rutherford (Krasinski), aka The Bullet, is the most talented player Princeton has seen, but won’t be turning pro any time soon. When Dodge Connelly (Clooney), who is trying his hardest to make the pros more professional, asks him what he’ll do with himself after leaving his college and his sport behind, Carter has a natty reply: Yale Law School and a job at a Boston firm. Lexie Littleton (Zellweger) is the shit-talking Chicago Tribune reporter assigned to dig up dirt on the squeaky clean Bullet and to serve as the too-obvious love interest for the two men.

After the requisite glad-handing, Carter joins up with Dodge’s Duluth Bulldogs, a team of ragtag men with names like Bakes, Curly, Hardleg, Ralph, Stump and Zoom. But along with Carter’s talent and charm come radical improvements for his teammates like diet, exercise and sleep. If the Bulldogs want to win games, Carter insists, they’re going to have to change.

Clooney recognizes and plays up the similarities between football’s era of change and that of Charlie Chaplin’s “Modern Times.” Clooney is the Tramp-like Dodge to Chaplin’s original Tramp; where Chaplin struggled to have his fun in a world taken over by capitalist factory managers, Clooney struggles to play his game in a world increasingly run by rules.

Clooney, as both actor and director, adopts the mode of Chaplin for his own burlesque purposes. Randy Newman’s original vaudevillian score — playing constantly — situates “Leatherheads” firmly in the Roaring Twenties, but proves a bit much at times. You start to wish the Bullet would take out the goddamn nickelodeon player instead of the other team’s receiver. The constant tinkle of a piano or bleat of a trumpet leaves no room for a silent unfolding of plot or building of tension. With such shallow characterization and such a hyperactive score, one expects the rakish guys and swingin’ gals to burst into song at any minute.

“Leatherheads” can’t get enough of football and newspaper metaphors. I certainly missed things along the way because of my football illiteracy: A crack about a kicker who “hooked it” left the guys behind me hysterical and me a little confused. But the most important references are obvious. Old man Dodge wants to keep things his way, and young Carter wants change. The more talented Carter sums it up: “My plays are a lot like your plays, but more effective,” he says, and we know he means both on and off the field.

With everyone in the movie trying to run their own plays and achieve their own ends — Lexie wants a juicy story, Dodge wants to do the pros his way, Carter just wants to be happy — the main engine moving the plot along is our desire to see which play will make for a win. Farce and slapstick abound, but there are no moments of poignancy or pathos. In fairness, Clooney probably wasn’t shooting for that, though at times you wish he had. There is clear potential for the chemistry between Zellweger and Clooney to develop into something more mature than an eighth-grader throwing baking soda and vinegar together, but because Randy Newman won’t shut up, the potential is unrealized.

“Leatherheads” is, in the end, a lot of show and not a whole lot of substance. There is plenty to listen to (Newman is, admittedly, a great composer) and plenty to look at (Clooney and Krasinski are handsome as ever), but there is very little to sink one’s teeth into. There is no Hail Mary at the end of this game, no scoop in the lead story and the audience is relieved to see the players finally jog off the field as the credits roll.