If the NFL football players went out on strike to support the referees in their negotiations over wages and working conditions, it would be considered a sympathy strike.

Sympathy Strike

A labor strike by workers in one union in support of workers in another union who are engaged in a dispute with their employer.

NFL

The National Football League, a professional American football league consisting of 32 teams, divided equally between the National Football Conference (NFC) and the American Football Conference (AFC).

Referees

Officials in sports contests responsible for enforcing the rules of the game, ensuring fair play, and in some contexts, mediating disputes between parties.