Cunningham (neck) was placed on injured reserve Thursday, Rich Hammond of the Los Angeles Daily News reports.
Cunningham had already been ruled out for Thursday's game against the Seahawks after failing to practice throughout the short week, but the team has now elected to shut down Cunningham with the season nearing its conclusion. Malcolm Brown and Chase Reynolds would be in line to back up Todd Gurley, while Mike Thomas will likely return kicks with Cunningham out.