Wide receiver Antonio Brown voiced his displeasure over social media after being fined $53,950 by the Oakland Raiders for skipping a mandatory walkthrough on Aug. 22 as well as a training camp session four days earlier.

Brown shared the following two-graph letter signed by Raiders general manager Mike Mayock over Instagram:

“Dear Antonio: As you know, you did not participate in the Raiders’ walk through on August 22,” the letter begins. “Your absence from practice was unexcused. Accordingly, you are hereby fined $13,950 pursuant to Article 42, Section 1(a)(viii) of the NFL Collective Bargaining Agreement and the Raiders’ Club Discipline Schedule.

“You were previously fined $40,000 for missing Raiders’ preseason training camp on August 18. 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 Club’s 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.”

Brown wasn’t pleased with the letter, judging by his response.

“When your own team want to hate but there’s no stopping me now devil is a lie,” Brown wrote in the caption. “Everyone got to pay this year so we clear.”

Brown has dealt with blistering feet as a result of a frostbite mishap during cryogenic therapy as well grievances involving his helmet during the offseason.

The 31-year-old Brown, however, is expected play in the season opener against the Denver Broncos on Monday.

The Raiders acquired the seven-time Pro Bowl selection from the Pittsburgh Steelers in a trade in March and later signed him to a three-year, $50.125 million contract.

Brown caught at least 100 passes and exceeded 1,200 receiving yards in each of the past six seasons with the Steelers. He appeared in 130 games with Pittsburgh from 2010-18, catching 837 passes for 11,207 yards and 74 touchdowns.