NAPA, Calif. — 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 walkthrough without wearing a helmet and then went into the weight room as the rest of his teammates stretched. Brown 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.

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. Brown 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.

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