CBSSports.com reported on Wednesday that Brown is facing a four-game suspension for violating the NFL's performance-enhancing substance ban.
Brown -- who spent last season on New York's practice squad -- is appealing the ban.
"I don't know what I can and cannot say," he said. "It was something that I've been on since I've been in the league, which was Adderall. I just forgot to fill out some paperwork and that was it."
Adderall is a is a brand name of amphetamine medication used for attention deficit hyperactivity disorder and narcolepsy.
Skeptics might be apt to draw a connection between the ban and the added bulk on Brown's frame. Brown weighed 224 pounds when the Giants took him in the fourth round of the 2009 NFL Draft, but the back is now a sturdy 240 pounds. He told CBSSports.com the Giants staff is "looking for me to be the biggest back."