Brown signed a three-year extension with about $30 million guaranteed after being acquired from Pittsburgh in March for two draft picks. Hope was in the air.

Then he reported to training camp with an undisclosed foot injury and posted a picture of his badly blistered, peeling feet on Instagram. In the image, Brown wore a big smile. Reports, notably on NFL.com, said that Brown entered a cryogenic therapy chamber without proper footwear and got frostbite.

Brown then refused to practice because the helmet he preferred was banned in the off-season by the N.F.L. and the players union because it, and other models, did not meet safety standards. This week Brown announced via video on the helmet-maker’s website that he had found a replacement.

Brown objected anew when the team fined him almost $54,000 for failing to practice with the team, and other infractions. He posted a photo on social media of the letter informing him of the fines. Brown and General Manager Mike Mayock reportedly argued about the fines. On Thursday, some media reported that Brown threatened Mayock, and that the team was considering suspending the receiver for several games.

On Friday, the Raiders played down the dispute, and head coach Jon Gruden said Brown would be with the Raiders when they open the season against the Broncos.

Brown posted a message on his Instagram account on Saturday morning saying that he was misunderstood and unappreciated, and wanted to move on. “Release me @Raiders #NOMore,” he wrote.

That came after he posted a video on YouTube that included what appeared to be a taped phone conversation between the wide receiver and Gruden. Gruden is heard asking Brown whether he wanted to be a Raider and if he was ready to play. Brown said he was a Raider and had been working hard. It is unclear whether Gruden knew he was being recorded, or whether he authorized its use. ESPN later reported that Gruden was “truly amused” by the video and thought it was “awesome.”