ALAMEDA (CBS SF/AP) — Star receiver Antonio Brown was back on the field for the Oakland Raiders on Tuesday after missing the previous practice as part of his dispute with the league and union over his helmet.

Brown took part in a walk through without wearing a helmet and then went into the weight room as the rest of his teammates stretched.

He came back out toward the end of the stretch but wasn’t wearing a helmet like all of his teammates who were practicing. The Raiders then held a brief practice out of view of the media.

After the walk through, head coach John Gruden told reporters “he’s (Brown) in, he’s all in, that’s what he said…He’s all in and ready to go. We’re happy to have him out here.”

As to where he is in terms of preparation, Gruden said: “He’s shown a great retention of what we are doing. He didn’t miss the off-season program. He’s been here, out here, in meetings. He’s in great shape. He’s running hard and running good routes.”

Gruden said Brown did wear a helmet during the short practice.

“Yes he did,” the Raiders coach said with a smile. “It’s a certified helmet.”

Brown didn’t attend practice Sunday as he works to find a helmet that he’s comfortable using and that meets safety standards set by the NFL and NFLPA.

He lost a grievance last week while seeking to use the Schutt Air Advantage helmet he has worn throughout his career. The helmet was too old to be certified as safe. He is still fighting with the league and union to find a suitable helmet.

General manager Mike Mayock gave Brown an ultimatum Sunday to be “all in or all out” and the receiver returned to the team for meetings the following day.