For the second time this month, an independent arbitrator has concluded a grievance hearing regarding Antonio Brown‘s helmet (via NFL.com’s Ian Rapoport). A ruling is expected to come next week, according to one source.

This seemingly minor issue has had – and may still have – major implications for Brown and the Raiders. The NFL barred Brown from playing with his beloved Schutt AiR Advantage helmet and the wide receiver reportedly walked out of training camp due to his dissatisfaction. Later, agent Drew Rosenhaus claimed that Brown’s absence was actually due to the malady he sustained while receiving cryotherapy treatment.

Brown is now back in camp and practicing with a certified helmet, but there’s no telling what could happen next with the mercurial star if he does not win his second grievance. The 31-year-old has not suited up for preseason action in the midst of all of this and it not be a shock if he were to change course yet again before the start of the season.

The Raiders open their season in Oakland on Sept. 9 against the Broncos.

Raiders GM Mike Mayock expressed his frustrations with Antonio Brown over the weekend, and he implied that he wouldn’t entertain Brown’s drama much longer. Mayock said, “[h]e’s upset about the helmet issue. We have supported that; we appreciate that. At this point, we’ve pretty much exhausted all avenues of relief. From our perspective, it’s time for him to be all-in or all-out.”

Whether Mayock’s words were the impetus behind it or not, Adam Schefter of ESPN.com reports that Brown — who reported to practice on Monday, though the club’s walk-through was ultimately canceled — practiced today with a certified helmet (Twitter link). Obviously, that’s a good sign for the Raiders, as it suggests that even if Brown loses his second helmet-related grievance, he will play nicely and go along with whatever headgear the league tells him he must wear.

Speaking of that second grievance, Ian Rapoport of NFL.com tweets that an arbitrator will hear Brown’s case on Friday, so this matter should be wrapped up fairly quickly. But since Brown is involved, it’s hard to say for certain.

Brown, of course, had been trying to have his prized Schutt AiR Advantage helmet certified by the league, and Daniel Kaplan of The Athletic says that the NFL’s Canadian testing lab has ordered some 2011 Schutt helmets from Virginia Tech (Twitter link). Earlier reports suggested that a 2011 Schutt AiR Advantage failed safety testing, but perhaps the league is attempting to compromise by finding AB a different model from the same maker.

We should have some more clarity after Friday’s hearing, but you can probably expect to hear more Brown-related reports in the meantime.

Antonio Brown may have reported to Raiders practice today, but the drama is far from over. Pro Football Talk reports (via Twitter) that the star wideout has filed a second grievance against the NFL for their unwillingness to let him wear his desired helmet. NFL.com’s Ian Rapoport tweets that the grievance will be heard on “an expedited basis.”

Specifically, Brown is upset that the league won’t let him wear any “Schutt AiR Advantage helmet less than 10 years old.” Rapoport tweets that the receiver believes “he should be afforded the same right provided to other NFL players to have a 1-year grace period to phase out his helmet in 2019 season.” Mike Florio of ProFootballTalk.com writes that the NFL allowed Patriots quarterback Tom Brady to play last season with a helmet that wasn’t deemed safe.

The 31-year-old’s first grievance against the NFL ended with an arbitrator ruling against the wideout. As our own Zach Links detailed, Brown’s preferred helmet is too old to be re-certified, and this means the helmet is not sanctioned by the National Operating Committee on Standards for Athletic Equipment. Brown had previously threatened to retire if the league would not let him wear his preferred headgear.

Brown showed up at the Raiders’ facility Monday morning and was in attendance for the daily team meeting. The wideout has put the Raiders through the ringer in recent weeks. A cryotherapy mishap left the wide receiver with a foot injury, which was believed to have been the cause of his training camp absence. Instead, the no-show was attributed to the helmet dispute.

Antonio Brown missed another Raiders practice on Sunday. While Brown is still dealing with feet issues, Mike Mayock confirmed this latest absence was related to his helmet. The Raiders’ supportive tone has shifted.

“He’s upset about the helmet issue. We have supported that; we appreciate that,” Mayock said, via Vic Tafur of The Athletic (video link). “At this point, we’ve pretty much exhausted all avenues of relief. From our perspective, it’s time for him to be all-in or all-out.”

The first-year GM reiterated hope Brown will be a major part of this new Raider regime’s attempt at a bounce-back season, but the team is clearly frustrated with its trade acquisition’s recent antics. An arbitrator ruled in favor of the NFL regarding Brown’s helmet grievance, and despite the four-time All-Pro finding a slightly newer model of his since-discontinued helmet, he’s been informed it failed an NOCSAE test.

Mayock’s comments run counter to Jon Gruden‘s last weekend. Oakland’s HC expressed support for Brown on both the helmet and foot fronts. A week later, it appears the 31-year-old superstar is testing the limits of another franchise.

The ball will be in Brown’s court. Mayock’s comment comes after the 10th-year wideout said the report of him again threatening to retire was false. We’re back in a holding pattern with Brown, whose holding pattern in Pittsburgh earlier this year led to his Bay Area relocation.

“I don’t know where they got that from, or who made that up, either,” Brown said, via NBC Sports Bay Area’s Scott Bair. “Why would I retire, man? I have a beautiful career. I’m healthy. I love to play the game.”

Brown reported back to the Raiders after his helmet grievance failed. But he has not given up in his interesting quest at headgear continuity. Brown’s camp said this week the Raiders informed Brown if he found a newer model (made since 2010) of the helmet he’s worn throughout his career it could be certified by the NOCSAE, Mike Florio of Pro Football Talk reports. It was not. The camp also believes the NFL moved to keep the receiver from wearing a newer model of the helmet, with a 2011 Schutt AiR Advantage model only failing to pass the league’s new safety-based guidelines once Brown caused this stir. Nevertheless, the Schutt AiR Advantage helmet is banned, Bair tweets.

However, the NFL and NFLPA worked together in the process that led to Brown’s latest helmet solution being tested (and failing), Tom Pelissero of NFL.com reports (on Twitter). The sides jointly said earlier this week the helmet would be tested in the same lab as the other league-approved helmets. Both the league and the union concurred Brown will not be allowed to wear that helmet in games.

While Brown is losing this battle, and is the only player waging it, he is clearly not going down without a fight.

Antonio Brown reported to training camp on Tuesday, but he brought his good friend and agent Drew Rosenhaus with him. When speaking with reporters, Rosenhaus claimed that Brown’s absence was more about his foot issue than his helmet kerfuffle (Twitter link via Vic Tafur of The Athletic). 

According to the agent, Brown’s return was not linked to Monday’s loss in arbitration that barred Brown from wearing the same headgear. Instead, Rosenhaus says it’s all coincidental – he claims Brown returned on Tuesday because his off-site treatment just recently wrapped up.

For those still tuned in on Brown’s helmet saga – if Brown finds a helmet with the same design that he feels comfortable with, he may be permitted to wear it. However, that helmet will be subject to testing and the approval of NFL and NFLPA officials (Twitter link via Peter King of NBC Sports).