The NFL has taken the highly unusual step of firing down judge Hugo Cruz for performance reasons.

It is the first time the NFL has fired an official in-season during the Super Bowl era because of performance.

Cruz, who last worked in Week 6 and is no longer an NFL employee, joined the NFL in 2015. He was responsible for one high-profile mistake this season when he missed an obvious false start by Los Angeles Chargers left tackle Russell Okung on a scoring play in Week 6 against the Cleveland Browns. He did not work in Week 7.

Otherwise, the details of the league's decision -- including other mistakes Cruz is presumed to have made -- are unknown.

An NFL spokesman declined to comment.

"The NFL has a troubling history of knee-jerk reactions with an eye on public relations, and clearly it has not learned from past mistakes," said Scott Green, executive director of the NFL Referees Association. "The NFLRA will protect the collectively bargained rights of all officials and will challenge this reckless decision through the grievance process."

The NFLRA, as allowed by its collective bargaining agreement with the NFL, has up to 90 days to file the grievance.

Sources reached by ESPN insisted there was no indication that Cruz committed an off-field mistake or that his firing was in any way disciplinary.

The NFL grades officials on their performance on every play of every game. The league has occasionally suspended or reassigned officials for mistakes of game administration, but it evaluates their careers on a yearly basis by placing each in one of three tiers.

Tier I is for the top performers, Tier II is for midlevel grades and Tier III is for the lowest-performing officials in a given year. Historically, two consecutive seasons in the third tier makes an official vulnerable to termination.

That system is designed to prevent instant evaluations based on a single mistake or a series of closely timed mistakes.

The NFL's quick decision on Cruz will send shock waves through the officiating ranks. Officials who once could be assured that their season would be evaluated through a larger lens will now be left to wonder if they could receive a career-ending phone call after one bad game.

FootballZebras.com first reported news of Cruz's firing.