New on SI: Out From the Dark: Sam Shields’ Two-Year Journey Back from Concussion

It was just one of those plays—in the 2016 season-opener, the Packers’ Pro Bowl corner went in for a clean tackle and came up groggy. Suffering the after-effects of concussion, Sam Shields spent days and months in darkness, shut off from the world, before finally determining to battle back. Two years on, he’s a key defensive and special-teams cog on a Rams club with Super Bowl aspirations.