I Love You, Man works as a full-court press on the idea of bromantic comedy thanks to the star players around whom director / co-writer John Hamburg has assembled a team.

This tale of blossoming guy love is little more than an excuse for Paul Rudd and Jason Segel to trade riffs. A nebbish bridegroom with no male friends (Rudd) auditions a charming alpha-male raconteur (Segel) to be his best man. It’s a duo of stud starters holding court long after the game’s been decided — Segel as the towering-Frankenstein center, Rudd as the versatile, nimble small forward.

That’s because Hamburg, as he did with Along Came Polly, ultimately values his cast of comedians over the logic of the laughs. Jon Favreau, Andy Samberg and J.K. Simmons are just three comic actors given short shrift in a star-studded cast, and why Samberg (as Rudd’s gay brother) couldn’t be his best man is never really addressed.

Plus, unlike last year’s Role Models (also starring Rudd), Man ultimately wanders from, rather than builds upon, whatever momentum it kicks up toward the finish. But there’s mas-macho subtext aplenty explored with flair, many bust-a-gut bits and arguably better chemistry between this film’s friends than most movies’ lovers.

As real-estate novice Peter Klaven, Rudd takes a hard turn away from his Models misanthrope. Peter is a mensch so doe-eyed he doesn’t even realize that not having a male confidant poses a problem. It’s not until he overhears friends of his fiancée, Zooey (Rashida Jones), expressing concerns that he’ll get too clingy, too emotional, too … girlish.

So Peter embarks on a manhunt for someone to stand beside him at his nuptials and, moreover, be his best dude. Peter negotiates squeaky-voiced gym rats (the incomparable character-actor comedian Joe Lo Truglio) and grudge-holding gay men (Reno 9/11!’s Thomas Lennon) before finding “the one.”

Sydney Fife (Segel) is an investor with a man-cave (complete with a masturbation station) — the slob Oscar to Peter’s fussbudget Felix who shrewdly observes the mechanics and mannerisms of male behavior. In time, Sydney pulls Peter out of his effeminate shell, although at what cost to his steadfast commitment to Zooey?

Rudd has conquered slapstick and puns (Anchorman: The Legend of Ron Burgundy) and acidic cynicism (Models), and here shows a knack for verbal gaffes that make Michael Scott look confident by comparison. A shy guy around his new friend, Peter drops phrases like “totes magotes” (meaning “totally”) or nonsensical nicknames for Sydney like “Jobin.” Each of Rudd’s many –isms makes for crafty cringe comedy.

Segel proves better as a straight-up comedian than a creative force; I Love You, Man is 1,000 times sharper and funnier than the overrated Forgetting Sarah Marshall, which Segel wrote. Segel’s profane physical reaction to a golf ball banging off his shin, and his slumped posture — Sydney always looks as if he’s proudly getting blown back by a wind — is perfect for the shabby-chic character he creates.

Hamburg leans too heavily on red herrings that Sydney isn’t all he claims to be; is he unemployed, or perhaps looking to fleece Peter’s savings? And there are 15 minutes of supporting-player improvisational riffs tacked on in favor of a fuller script.

But in the end, Hamburg’s emphasis on the music of Rush nicely sums up his core question: Where is that middle ground for males between the rowdy-cornball rock ‘n’ roll of Rush and the respectability of settling in for Sunday-night HBO programming? By putting the rock in Rudd and Segel’s capable hands, Hamburg ensures that I Love You, Man never lets up on its tenacious glee.