Arnold (shoulder) was placed on injured reserve Monday, Eric Woodyard of ESPN.com reports.

EDGE Analysis

Arnold made his return to action in the team's 34-27 loss to the Packers on Thanksgiving after missing two games while recovering from a concussion. The cornerback recorded four solo tackles in the contest, but he may have suffered a shoulder injury in the process. Arnold missed a pair of contests in October with a shoulder injury, and it's unclear if he aggravated that issue or if he suffered a new injury. The 22-year-old popped up as a non-participant at the team's practice session Monday, and he's now set to undergo shoulder surgery this week, which will sideline him for the rest of the regular season, per Tom Pelissero of NFL Network.