Dwight Clark, a wide receiver for the San Francisco 49ers during the team's heyday in the 1980s, disclosed Sunday that he has a debilitating illness.

The Mercury News said Clark was diagnosed in 2015.

The newspaper said Clark, a two-time Super Bowl winner, said in a note: “I have ALS, also known as Lou Gehrig’s disease. Those words are still very hard for me to say.”

Clark played nine seasons for the 49ers and was one of Joe Montana’s favorite targets. He had 6,750 receiving yards in his career, which is third on San Francisco’s all-time list, behind Terrell Owens and Jerry Rice.

In the 1982 NFC Championship game, with less than a minute to go, Montana rolled to his right and threw a ball that most thought he was trying to throw away. But Clark jumped high and hauled it in, and the play was immediately anointed, "The Catch." Sports Illustrated ranked it No. 33 on the list of 100 greatest plays of all-time.

The news comes on the same day the family of football legend and Hall-of-Famer Gale Sayers announced he has dementia.