King suggested the option in his column Monday, writing it's something "every agent and knowledgeable player would absolutely dread." The letter would force Brown to report to Raiders camp by the end of the week or be placed on the reserve/left squad list, which would make him ineligible for the entire 2019 season and forfeit the guaranteed salary on his contract.
Brown was absent from Raiders practice Sunday, once again in protest of the league's ruling on his Schutt Air Advantage helmet. Ian Rapoport of NFL Network reported Brown is currently having the league safety-test two different models of the helmet that was denied last week.
The NFL banned the Schutt Air Advantage last week after having it undergo safety testing. Brown had previously lost a grievance against the league in hopes of wearing his preferred helmet, which he has used his entire career. The NFL previously stated Brown could wear a version of the helmet that was less than 10 years old, but Pro Football Talk reported the league switched its stance after the helmet failed safety testing.
Raiders general manager Mike Mayock expressed his frustration with Brown's continued practice absences Sunday:
"Antonio Brown is not here today, and here's the bottom line: He's upset about the helmet issue. We have supported that. We appreciate that. We have, at this point, exhausted all avenues of relief. From our perspective, it's time for him to be all in or all out.
"We're hoping he is back soon. We have 89 guys busting their tails. We are really excited about where this franchise is going, and we hope AB is going to be a big part of it starting Week 1 against Denver. End of story. No questions."
The helmet issue has been an ongoing saga throughout the summer, resulting in Brown missing numerous practices. He has also missed time after suffering extreme frostbite in his feet after failing to wear proper protection in a cryotherapy chamber.
Agent Drew Rosenhaus appeared on ESPN's Get Up! on Monday morning, saying he expects Brown back at Raiders camp soon. However, he acknowledged Brown takes the helmet issue seriously and wants to wear his preferred equipment.
"Antonio is very genuine. He wants to be there, he wants to be part of the team, he wants to practice," Rosenhaus said. "But he'd also like to do it with the helmet he's worn his entire life...this is his life. He's risking everything. He's got a family, he's had a concussion before. This helmet has kept him safe. He's had brutal hits, and we're just trying to find a way to work it out."
The Raiders owe Brown $29.1 million in guaranteed salary over the next two seasons. If they send him the five-day letter and he does not report, those guarantees would be off the table. They could also suspend him for conduct detrimental to the team and void the guarantees.