• Antonio Brown has been day-to-day at Oakland Raiders training camp with a somewhat mysterious foot issue.
  • According to a report, Brown suffered frostbite on his feet from going into a cryotherapy machine without proper footwear.
  • Brown posted a picture on social media showing what appeared to be severely blistered feet. It’s unclear the severity of his foot issue and if it will keep him sidelined for long.
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Antonio Brown hasn’t gotten the type of start he would have liked with the Oakland Raiders because of a lingering, mysterious foot injury.

Brown has been day-to-day and on and off the field during training camp. Raiders head coach Jon Gruden told reporters on Tuesday that Brown was not at camp because he was “gathering information” on his feet.

Brown had posted a picture of his feet on social media, showing what appeared to be intense blistering.

According to Pro Football Talk’s Chris Simms, the injury may actually be the result of frostbite. According to Simms, a source said Brown got into a cryotherapy machine without the proper footwear and suffered frostbite.

The newest season of HBO's "Hard Knocks" debuted on Tuesday featuring the Raiders, but Brown's feet weren't addressed other than a trainer telling Gruden that Brown was struggling to make hard cuts.

It's unclear how serious the issue is. The Raiders have not offered many comments on what's ailing Brown or how long he could be out. The issue was thought to be "very minor," per ESPN's Field Yates. However, Brown went to see a foot specialist this week.

The Raiders had a splashy offseason, which included trading two draft picks to pick up Brown. While they're poised to make big improvements this season, much of it will be reliant on their No. 1 wide receiver's health.