When Antonio Brown arrived at Oakland Raiders training camp late last month, he was immediately placed on the non-football injury list due to, what was a the time, an undisclosed issue.

Brown came off of the list less than 48 hours later and partially practiced, but he has not practiced since.

It was then revealed that Brown sustained frostbite on his feet from spending time in a cryotherapy chamber in France without wearing the proper footwear.

While that is the widely accepted reason for Brown's foot issues, his agent, Drew Rosenhaus, would not confirm nor deny, saying he can't get into details of how it happened because there might be legal action, according to Vic Tafur of The Athletic.

Of course, Brown's feet were not the only reason—and probably not even the main reason—why he was sitting out, as he was also embroiled in a battle with the NFL over the usage of his helmet, which was banned by the league for no longer being certified by the NOCSAE.

The wide receiver, who threatened to walk away from the game if the league did not allow him to wear the helmet he had worn the first nine years of his career, then filed a grievance against the NFL and lost.

But, it does not look like Brown will be retiring anytime soon, as he took to Twitter after the decision to announce that he would soon be rejoining his teammates. He then returned to training camp on Tuesday.

The Raiders acquired the 31-year-old in a trade with the Pittsburgh Steelers earlier this offseason.