Raiders general manager Mike Mayock gave Antonio Brown an ultimatum, and it appears for now the star wide receiver is playing ball.

The next chapter of the never-ending Helmetgate saga began Tuesday when Brown showed up for Raiders practice with a certified helmet, answering Mayock’s “all in or all out” threat issued to reporters on Sunday.

Jon Gruden was asked if Brown was indeed all in.

“Is that some sort of joke? Yeah, he’s in, all in, that’s what he said,” the coach told reporters.

Regarding the helmet Brown had, Gruden said, “It’s a certified helmet. He’s all-in, ready to go.”

This came a day after reports surfaced that Brown, 31, filed a second grievance against the NFL in an attempt to wear the same helmet he’s worn throughout his career, one that is no longer certified because it doesn’t meet safety standards.

“This grievance thing is no laughing matter,” Gruden said. “It’s something that’s really important to him. And there’s nothing wrong with supporting your players on things that they believe in. We also understand the league’s position, but I’m confident that he’s gonna be a heck of a player for us and be ready to roll.”