EVANSTON, Ill. » Northwestern University’s football players will cast ballots Friday on whether to form the nation’s first union for college athletes — a potentially landmark vote that will be kept sealed for months and possibly years.

The National Labor Relations Board said Thursday it will hear an appeal by Northwestern challenging the decision from a regional NLRB director who ruled the players are university employees and thus have the right to unionize. The board said the ballots will be impounded at least until it issues its decision later this year. If the case lands in court, it could be a far longer before the results of the vote are known.

The vote comes one day after leaders at the NCAA endorsed a dramatic proposal to give its biggest and most powerful member schools the autonomy to make decisions for its athletes, including more robust funding of scholarships, the ability to address health concerns and other key areas. Unionsupporters say they are seeking guaranteed coverage of sports-related medical expenses for current and former players.

There have been no raucous rallies or demonstrations on the 19,000-student campus just north of Chicago, just official notices about the vote posted near the Wildcats’ locker room. But there has been plenty of lobbying in the form private meetings, calls and emails, and everyone from coach Pat Fitzgerald to NCAA President Mark Emmert has called for a "no" vote.

The 76 scholarship football players eligible to cast ballots know the spotlight is on them, said Ramogi Huma, president of the College Athletes Players Association, which would represent the players at the bargaining table if the pro-union side prevails.

Some of the pressure they feel stems from dire Northwestern claims about the consequences of unionization, he said.

"They’re looking at anything and everything to invoke fear in the players," said Huma, a former UCLA linebacker and longtime critic of the NCAA. "We feel like some of the tactics are scare tactics."

Northwestern, which is required by law to let the vote proceed, denies applying undue pressure on players to vote "no." However, it recently sent a 21-page question-and-answer document to the players outlining the problems with forming a union. In it, Northwestern said it hoped unionization would not lead to player strikes in the event of a dispute — but if it did, replacement players could be brought in to cross picket lines.

"The tension created in such a situation would be unprecedented and not in anyone’s best interest," it said.

The school also said divisions could emerge between scholarship players eligible for union membership and walk-ons, coaches and staff.

"There is no question but that the presence of a union would add tension in terms of creating an ‘us’ versus ‘them’ feeling between the players it would represent and those it would not," it said.

Northwestern did not release the document publicly, but The Associated Press obtained a copy and a spokesman for the university’s athletic department, Paul Kennedy, verified its authenticity. Alan K. Cubbage, the school’s vice president for university relations, dismissed Huma’s suggestion that the school was using scare tactics

"I would say strongly that Northwestern has conducted an election campaign … according to the procedures and the rules of the NLRB," he said.

When outgoing Northwestern quarterback Kain Colter announced in January that he would lead the drive to unionize, helped by CAPA and the United Steelworkers, he said nearly all of his fellow teammates were behind him.

Safety Davion Fleming said his teammates slowly began to understand the issues aren’t clear-cut.

"When the union talk initially started, it wasn’t very clear what was going on," said Fleming, who can’t vote because his eligibility is exhausted. "I think they didn’t understand the implications."

Huma said Northwestern seemed to be intentionally misconstruing the facts, and said the school’s "subliminal messages" included the suggestion that a "yes" vote could throw their amateur status into question.

"No one is taking about striking," he said. "They are trying to rattle players."

The fight has been noticed by incoming recruits, too.

"I went there for many reasons, more than just football," said Justin Jackson, a running back recruit from Carol Stream. "There’s no possible way that it would have deterred me from signing back in February."

Like the players themselves, recruits and their families have a long list of potential questions should a football players’ union become a reality. One of the biggest issues is whether scholarships would be counted as taxable income.

"I don’t feel that we’re really in the position to get involved in anything like that with it yet," said Phil Jackson Sr., Justin’s father. "But it does obviously would have an impact on the students as far as the scholarship not being a grant but actually being considered income, yeah, that definitely would be a concern.

"But at the same time we also understand there’s some important issues that need to be hashed out and we’re kind of letting the process play itself out for right now."

Trevor Siemian, who is expected to replace Colter as the starting quarterback, has said he will be voting against a union.

"I’ll say there’s a significant number of guys on the team who feel the same as me," Siemian said earlier this month.

Fleming also said doesn’t support unionization, though he said the drive has prompted a much-needed debate about conditions for players. After weeks of both sides vying for votes, he said he detects a common sentiment among players.

"They just want this to be over — and to focus on football," he said.

AP Sports Writer Jay Cohen contributed to this report.