Newly-adopted player-safety rules, while wholly necessary, already make one aspect of the job asked of defensive backs close to impossible. The last thing defenders playing in open space need is for the league to make it even harder for them to prevent catches in the first place, when tackling receivers after they've caught the ball seemingly grows increasingly difficult every season.

But after Monday's near-unanimous vote allowing pass interference judgement calls to be subject to a coach's challenge, defenses nevertheless find themselves on the losing end of another rule change, and some of the league's most prominent defensive backs are not happy about it. Responding to a critical tweet about the change by Los Angeles Rams safety Eric Weddle, four-time All-Pro cornerback Richard Sherman went so far as to allude to the possibility of referees intentionally, and retroactively, calling pass interference to sway the outcome of a game.

“Now they can control the outcome as they see fit,” he wrote. “Every defendable pass looks like PI in slow motion.”

Sherman's point about the pitfalls of slow-motion replay are well-taken. It's a tall task for the human eye to avoid interpreting contact as more significant than it actually was while assessing plays in slow motion. Officials have been attempting to avoid that inherent bias since the inception of replay review, though, and for the most part have escaped criticism for any perceived failure – justified or otherwise – to do so on a consistent basis.

Regardless, the San Francisco 49ers star and his fellow defensive players across the league have a right to be frustrated. Last season marked the NFL's third highest-scoring campaign of all time, and given these new rules, it seems ever likely offenses could rank up points at a record rate in 2019.