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."
Northwestern did not release the document publicly, but The Associated Press obtained a copy and the school 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.
Trevor Siemian, who is expected to replace Colter as the starting quarterback, has said he will vote against a union.
"I'll say there's a significant number of guys on the team who feel the same as me," Siemian said this month.
Safety Davion Fleming said his teammates have slowly begun to understand that the issues aren't clear cut.
"When the union talk initially started, it wasn't very clear what was going on," said Fleming, who doesn't support unionization but can't vote because his eligibility is exhausted. "I think they didn't understand the implications."
After weeks of both sides vying for votes, Fleming 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.
- Ranking the best running backs in BYU history
- Chris McGown resigns as BYU men's volleyball...
- Doug Robinson: Witt latest BYU runner chasing...
- Morning links: BYU's football schedule...
- Gallery of champions: All 94 state...
- Rock On: BYU finds another recruiting niche
- Morning links: NBA post-up is not dead;...
- Former Ute player among those invited to work...
- Report: Former Jordan High quarterback... 47
- Dick Harmon: NCAA's move to speed up... 46
- Rock On: BYU finds another recruiting... 36
- BYU basketball: NBA draft insiders... 31
- Morning links: BYU's football schedule... 31
- BYU football signs New Zealand rugby... 24
- Chris McGown resigns as BYU men's... 12
- Doug Robinson: Witt latest BYU runner... 8