When Brandon Marshall signed the largest contract for a wide receiver in Bears history, he donated $1 million to mental health causes.

He continued to support and raise awareness about mental health by wearing lime green shoes to a game against the Giants in 2013 knowing that he could get fined for it.

“I always say that football is not my purpose, it’s my platform,” Marshall said in the days leading up to that Giants game.

Marshall’s lime green shoes got some airtime during Mental Health Awareness Week. He ended up getting fined $10,500 by the NFL.

“When he knows he’s right about something he will advocate for it and push through it,” said Dr. Gail Grabczynski, lead mental health clinician for the Bears from 2005 to 2016. “That’s why he wore the neon green cleats and understood there was going to be maybe some backlash, but he was very confident that it was doing the right thing.”

Marshall’s stand drew more attention to the cause he was trying to raise awareness for.

“(Mental health) is kind of hidden and a lot of people wouldn’t like to share those things,” said Matt Forte, a teammate of Marshall’s for four years including in 2013. “He wanted to bring some attention to it. The fact that the NFL wanted to fine him, I thought it was kind of dumb because that’s what the whole NFL’s platform is for. To bring things that light needs to be shed on so that positive change can happen. That’s the only thing he was trying to do.”

See more from Marshall’s story in the video above.

This is all part of a larger message and project from the NBC Sports Regional Networks. Religion of Sports — the media company founded by Tom Brady, Michael Strahan and Gotham Chopra — has partnered with NBC Sports regional networks for a new one-hour documentary addressing the issue of mental health in sports. “HeadStrong: Mental Health and Sports” is executive produced by six-time NFL Pro Bowl receiver Brandon Marshall.

“Mental health issues have been pushed to the forefront of our national conversation,” Ted Griggs, president, Group Leader and Strategic Production & Programming, NBC Sports Regional Networks, added. “Thanks to athletes like Brandon Marshall, Kevin Love, Michael Phelps and Missy Franklin, and executives such as NBA commissioner Adam Silver, we know that our sports heroes face mental health challenges, just like so many others. We hope this project will advance that conversation and show people that resources and assistance are available to everyone.”