Antonio Brown left the practice field as soon as the Raiders put on helmets

Antonio Brown reportedly filed a second grievance against the NFL as he looked to wear his preferred helmet model — the discontinued Schutt Air Advantage.

But his refusal to partake in football activities with any other helmet is getting odd at this point.

Brown was present for the start of Raiders practice in Napa, Calif., on Tuesday. He went through stretches and warmups without a helmet — he wasn’t even holding a helmet unlike his teammates. Once his teammates put on helmets for the start of practice, Brown left the field and went towards the team’s weight room.

Reporters covering the practice took notice to the strange (and early) exit.

Though Tuesday’s practice was just a walk-through, it was noteworthy that Brown didn’t have a helmet with him at all for the media-viewing window.

He’s not allowed to use the banned helmet — even in practice — but he had tried out an approved helmet before the Raiders’ preseason game in Arizona.

Christian Petersen/Getty Images

Right now, though, Brown doesn’t look willing to compromise. He wants to wear his helmet.

UPDATE: Brown later returned an approved helmet outside of the media viewing period. According to Raders coach Jon Gruden, Helmetgate may be over.