Oakland Raiders star Antonio Brown expressed his frustration Wednesday with a notice that the team reserves the right to fine him for missing a practice and a walkthrough last month.

Brown received a letter from Raiders GM Mike Mayock saying he was going to be fined $40,000 for an unexcused absence from practice on Aug. 18 and $13,950 for skipping a walkthrough in Winnipeg on Aug. 22. From the look of Brown’s Instagram stories, it didn’t appear he was happy about it.

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“WHEN YOUR OWN TEAM WANT TO HATE BUT THERE'S NO STOPPING ME NOW DEVIL IS A LIE. EVERYONE GOT TO PAY THIS YEAR SO WE CLEAR,” he wrote.

The fines came in the middle of Brown’s saga over which helmet he was allowed to use. Brown reportedly threatened to retire if he couldn’t use the same equipment he had been using for the last 10 seasons, while Mayock challenged him to be “all in or all out.”

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“Please be advised that should you continue to miss mandatory team activities, including practices and games, the Raiders reserve the right to impose additional remedies available under the Clubs Discipline Schedule, the CBA and your NFL Player Contract, including, but not limited to, additional fines and discipline for engaging in Conduct Detrimental to the Club,” Mayock wrote in the letter to Brown.

Brown also announced Wednesday he would be wearing a Xenith Shadow helmet with this season. It had been rated as one of the top performers in testing done by the league.

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The Raiders acquired Brown from the Pittsburgh Steelers in the offseason.

The Associated Press contributed to this report.