The College Athletes Players Association filed a brief Wednesday responding to Northwestern’s appeal of last month’s ruling regarding the employee status of NU football players.

In March, the Chicago regional director of the National Labor Relations Board ruled NU’s football players are University employees and therefore legally able to unionize. On April 9, NU appealed the decision to the national office of the NLRB, arguing the initial decision was incorrect.

(Northwestern files union appeal to NLRB)

CAPA’s response allows the proposed union to rebut NU’s explanation. It suggested the University had no grounds to appeal and asserted that the NLRB’s ruling was appropriate.

“Northwestern’s entire position in this case is a castle built on sand,” the brief says. “In a meticulous and carefully reasoned decision, the regional director determined that the players satisfy the common law test of employee status … under which an employee is a person who performs services for another subject to the other’s right of control, in return for payment.”

There is no timetable for a decision from the NLRB. Players will vote on whether to form a union April 25, but the result of the vote will be impounded until the appeal is decided.