NFL Alum Chris Johnson Details Getting ALS Diagnosis at 39

"We hoped it was something else, but after thorough testing they finally came down with a diagnosis of ALS," Johnson, who now uses a speech-generating device to communicate, went on. "They told us about a medication that might extend life by a few months. Then they told us to get our affairs in order. It was hard hearing that."

Detailing the “shock” of the being diagnosed with the degenerative neurological disorder, the 40-year-old admitted his new reality still hasn't fully sunk in.

NFL star Chris Johnson opens up about finding the strength to speak out about his ALS diagnosis and how he was inspired by Eric Dane. pic.twitter.com/pI3BE73OdG

"Honestly, I don't know if you ever fully process it," Johnson shared. "At first, you're in shock. Then you realize you have two choices. You can give up, or you can fight. I chose to fight."

And he credits the late Eric Dane’s public advocacy surrounding the disease, including the Grey’s Anatomy alum’s own GMA interview alongside neurologist Dr. Merit Cudkowicz with helping to alter his outlook on his prognosis.

"After watching Good Morning America and seeing Dr. Merit with Eric Dane, we reached out to her," he said. "She was willing to think more creatively, offering experimental treatments that might help and advance research."

"We've been with her ever since," Johnson added, "and that changed the course of our fight."

As for why he's sharing his story now, the former Tennessee Titans player hopes to put a spotlight on the realities of the devastating disease.

"It's continued to progress much faster than I ever imagined," he said. "I want people to understand just how quickly ALS can attack your body. Just over a year ago, I was picking up my 7-year-old daughter so she'd make a wish with her birthday cake. Today, I couldn't do that."

"If sharing my story even helps one person get diagnosed sooner, inspires more research or gives another family hope," he added, "then it's worth it."

And as he’s battled, he’s had a support system led by wife Brittany with him at every turn.

"She hasn't left my side through any of this," he said of his wife, Brittany. "My kids are also a huge part of why I keep going. Every day I wake up wanting more time with them to make more memories and just be their dad. They give me a reason to keep fighting."