What happened: Former NFL running back Chris Johnson is calling for a revival of the Ice Bucket Challenge to raise awareness of ALS as he battles the progressive nervous system disease. The appeal comes days after Johnson publicly shared his diagnosis, and it has already begun circulating among former teammates and fans online.

Why it matters: The Ice Bucket Challenge became one of the most successful awareness efforts in sports history, and a public push from a well-known former player could renew momentum for ALS research and funding. Johnson's platform gives the cause immediate reach across the football community, where support has been building since he first revealed the diagnosis.

What to watch: Watch for players, teams and fans to take up the challenge and share it, and for updates on where donations and research funding are being directed.