Chris Johnson Diagnosed with ALS at Age 39, Titans Legend Won NFL OPOY Award in 2009

Retired running back Chris Johnson announced he has been diagnosed with ALS.

"There's no history of ALS in my family," the 39-year-old told Good Morning America's Michael Strahan on Monday. "My doctors believe my case is what's called sporadic ALS, which is actually how the vast majority of ALS cases happen. That's one of the reasons this disease can be so shocking. It can happen to someone who never expected it."

Johnson, who spoke to Strahan though an electronic device, said his condition has "continued to progress much faster than I ever imagined."

"I want people to understand just how quickly ALS can attack your body," he said. "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."

Tennessee Titans owner Amy Adams Strunk released a statement saying the organization is "holding him and his family close" in light of the news and the New York Jets also posted a statement:

Johnson said he's "still me" despite what the disease has done to him physically.

"ALS has changed what my body can do, but it hasn't changed who I am," he said. "People sometimes look at the physical disability and assume you're not still the same person inside. I still think the same. I still dream. I still love my family. My body just doesn't cooperate."

Johnson played 10 years in the NFL. He's most closely associated with the Titans, for whom he spent six seasons.

The three-time Pro Bowler was the 2009 Offensive Player of the Year after becoming the sixth running back to that point to eclipse 2,000 yards on the ground. Among Titans players, he's fourth all time in rushing yards (7,965) and touchdown runs (50).

Johnson last played for the Arizona Cardinals in 2017.