There's a roar from the stands at the Roosevelt High School football field—the kind usually heard only on those brisk fall nights when the Roughriders take the turf. A player dives, arms outstretched like Pete Rose, for an interception. He rises from the ground to even louder cheering from the 650-person crowd. With bright stadium lights bouncing off his green jersey, he launches a white disc 30 yards downfield.

Welcome to Major League Ultimate Frisbee, a new league where Portland is represented by a seven-man squad called the Stags. The Stags, sadly, are struggling. The team is in last place in the Western Conference of the bicoastal eight-team league, with a record of 1-5.

Partly, that's because arguably Portland's best player bolted for the Seattle Rainmakers. Mario O'Brien has been called the LeBron James of Ultimate Frisbee.

Not because he's as good as the Whore of Akron, but because after leading Portland's best-known club team for years, O'Brien abandoned the hometown crowd to play for a championship-caliber pro team. O'Brien—a full-time public-school substitute teacher and, along with a sizable percentage of Portlanders, my former roommate—takes the BoltBus to Seattle for games and weekly practice. Though Ultimaters rigorously defend a strict code of jovial sportsmanship—called "spirit of the game," or "SOTG"—some players have identified him—not the Rainmakers, but him—as their chief rival. 

O'Brien is unapologetic.

"There's an opportunity to play with one of the best coaches in the world, and I've never been coached in Ultimate in my whole life," he says. "I want to jump on a train that's already running, and I want to win."

Major League Ultimate is the most serious attempt yet at taking the Frisbee-based sport from the quad to a stadium. The rules are simple: Players toss a disc to teammates to move it toward the opponents' end zone. You can't run with the Frisbee. The opposing team takes possession of dropped passes or by interception. Chaos ensues as "cutters" dive, leap and eat dirt attempting to secure the disc.

Though players face constant injury—concussions, knee-ligament tears and broken bones aren't uncommon—they say their biggest challenge is overcoming stereotypes. They are not, they say, stoned frat dudes killing time between Phish shows. They are athletes.

"Misconceptions are: A, it's a game for hippies; B, we play with dogs," says Nathan Schorsch, 26, the Stags' general manager. "Everyone confuses it with disc golf. That’s completely different.” 

As the Stags take the field, Schorsch seems like a lifer as he gleefully argues with refs—zebras are found only at the professional level—and displays the chest-beating pride of a proud father. 

"If you had told me 10 years ago I'd be the manager of a professional Ultimate team, I would have had to call for an adult," Schorsch later says as he grins and sips a beer on the sun-drenched patio at Prost in North Portland.

According to Schorsch, Ultimate deserves it's name.

"In soccer, players usually play all 90 minutes, but they're not running all the time," he says. "A lot of our guys…they have to be running pretty much every second they're on the field."

For this, MLU pays them $25 per game. The league also shoulders the price of travel, uniforms, training and injury rehabilitation. Players engage in once-a-week practices and tough endurance- and strength-building exercises. 

Schorsch, a longtime Ultimate enthusiast, left Seattle late last year to run the Portland franchise. He quickly recruited some of the best players from Portland's acclaimed Rhino club team.

Rhino's leader and best-known player attended the first Stags tryout, then stopped returning calls.

That's O'Brien, a local institution known for developing a series of videos called Rise Up to teach players technique. In the past two years, he's traveled to eight countries on three continents to conduct clinics. The Wisconsin native with a penchant for random freestyle raps was featured prominently in Chasing Sarasota, a locally produced documentary about Rhino's bid for a national club title.

In the trailer, O'Brien says Rhino is "about building something with a group of guys that I care about."

Sarasota ends with a heartbreaking Rhino loss. O'Brien's guys are now in Seattle.

One thing everyone in Portland and Seattle can agree on is that the sport needs more fans.

The ghost of the Portland LumberJax—a professional lacrosse team that folded in 2009 after four seasons—looms large over discussions of how the Stags can break out of their small niche and become a phenomenon. So far, crowds have consisted mainly of members of the insulated Ultimate community.

The goal, players say, is to be more like roller derby, a niche sport with a larger loyal following. Eventually, they hope their popularity might even challenge the Timbers soccer team. O'Brien models his approach on Martin Luther King Jr.

"We're at a watershed moment, but I don't think we have any idea how big or how small the sport will end up being," O'Brien says. "How do you break racism? It's not by having someone tell you that you shouldn't be racist. It's by persistent communication over a period of time, and then it's a meaningful experience that totally changes your view. Eventually, you're where you are with civil rights and gay rights."

Perhaps more than anyone, Chasing Sarasota director Matt Mastrantuono understands the difficulty of getting  nonbelievers into the church of Ultimate. A longtime player forced into retirement after one too many on-field concussions, Mastrantuono quit his day job to fully commit to the dramatic movie's yearlong filming and editing. When it wrapped, he took the film around the U.S. and Europe, screening it mostly in cities with a built-in Ultimate community. It played like gangbusters.

"Ultimate is reaching a critical mass," he says. "People are pushing the envelope of the sport. People are starting to gravitate toward stars. Kids are looking up to them."

The rivalry between the Stags and Rainmakers is at once wholly palpable and barely perceptible: Sure, the competitive Rainmakers are an easy target for animosity, but members of the last-place Stags only speak negatively of them in hushed tones. That's largely because of the sport's cultish dedication to "spirit of the game." After all, this used to be a recreational game for most—albeit one taken very seriously—with traditions of goofy costumes and all-night ragers. 

Stags cutter Dan Shaw was nervous that tight-knit community would be lost in the pros. A veteran of co-ed teams, Shaw valued the sportsmanship and inter-team camaraderie. With the introduction of referees, video streams, announcers and, of course, paychecks, Shaw said he feared the first casualty would be the community that brought the sport to this level.

"A huge part of Ultimate is the spirit of the game," he says. "I was worried that was going to be lost, and that we were going to see egos going off. I've been happy with the interactions and demeanor with every team, but it's something that lingers in the back of my mind."

Instead, MLU players and administrators are seeking to embrace the game they love as it enters a brave new world—one where they're not stereotyped as barefoot burnouts suffering demoralizing defeats to well-trained Goldendoodles, where the sport and the players get the respect afforded to athletes in other alternative sports.

All agree it will take time, dedication and persistence. A local villain doesn't hurt, either.

"It's never going [be] baseball or football," O'Brien says. "But I think Ultimate has the ability to appeal to people who like niche sports. Just like there's professional roller derby, where it's entertainment and people are really competitive, I see parallels there.” 

GO: The Portland Stags play the Seattle Rainmakers at Renton Memorial Stadium, 405 Logan Ave. N, Renton, Wash., on Saturday, June 1. 12:30 pm. $8-$16.