Monday morning, the National Labor Relations Board overturned a ruling that would have allowed football players at Northwestern University to unionize.

Citing concerns a union would provide an unfair advantage in the college football arena between unionized schools and the un-unionized, the NLRB’s ruling was unanimous.

According to the Associated Press:

The National Labor Relations Board on Monday overturned a historic ruling that gave Northwestern University football players the go-ahead to form the nation’s first college athletes’ union, saying the prospect of union and non-union teams could throw off the competitive balance in college football.

The decision throws out a March 2014 ruling by a regional NLRB director in Chicago who said that the football players are effectively school employees and entitled to organize. Monday’s decision did not directly address the question of whether football players are employees.

The labor dispute goes to the heart of American college sports, where universities and conferences reap billions of dollars, mostly through broadcast contracts, by relying on amateurs who are not paid. In other countries, college sports are small-time club affairs, while elite youth athletes often turn pro as teens.

The unanimous ruling by the five-member National Labor Relations Board concludes that letting Northwestern football players unionize could lead to different standards at different schools — from amounts of money players receive to the amount of time they can practice. That would, it says, create the competitive imbalances.

The ruling applies to private schools, like Northwestern, which is a member of the powerful Big Ten Conference. Public universities do not fall under the agency’s jurisdiction, though union activists have said they hope Northwestern’s example inspires unionization campaigns by athletes at state schools.

Northwestern became the focal point of the labor fight in January 2014 when a handful of football players called the NCAA a “dictatorship” and announced plans to form the first U.S. labor union for college athletes. Quarterback Kain Colter detailed the College Athletes Players Association at a news conference, flanked by leaders of the United Steelworkers union that has lent its organizing expertise and presumably will help bankroll the court fight.

ESPN called the decision, “a major victory for Northwestern and the NCAA.”

“In the decision, the Board held that asserting jurisdiction would not promote labor stability due to the nature and structure of NCAA Division I Football Bowl Subdivision (FBS),” the NLRB wrote in its decision. “By statute the Board does not have jurisdiction over state-run colleges and universities, which constitute 108 of the roughly 125 FBS teams.

“In addition, every school in the Big Ten, except Northwestern, is a state-run institution. As the NCAA and conference maintain substantial control over individual teams, the Board held that asserting jurisdiction over a single team would not promote stability in labor relations across the league.

“This decision is narrowly focused to apply only to the players in this case and does not preclude reconsideration of this issue in the future.”

The sentiment was also mirrored in the AP report:

Northwestern, the Big Ten and the NCAA all argued against the unionization effort, saying that lumping college athletes into the same category as factory workers would transform amateur athletics for the worse. At one point, Northwestern administrators sent a document to players outlining potential pitfalls, noting that player strikes could lead to the spectacle of replacement players.

Follow Kemberlee Kaye on Twitter @kemberleekaye