In a series of emotional and expletive-filled tweets, McClain said his brain is tired and he needs to get his "head checked."

"Need to tell my story of how my head is crazy and how football did it," McClain wrote. "Please someone help me get this out the @NFL puts paperwork in out (sic) faces and thats it."

Reports show an increasing number of retired NFL players who have suffered repetitive hits to the head have developed memory and cognitive issues such as dementia, Alzheimer's, depression and chronic traumatic encephalopathy (CTE). CTE is a degenerative disease of the brain and is associated with repeated head traumas like concussions.

The NFL acknowledged a connection between football and CTE for the first time in 2016 and has since rolled out initiatives intended to increase the game's safety and to prevent and treat head injuries.

But McClain said he hasn't received the treatment he needs and called on the NFL for help.