Denver Broncos wide receiver Emmanuel Sanders was knocked out of the game against the St. Louis Rams when he suffered a concussion on a jarring hit by Rodney McLeod.

McLeod drew a 15-yard penalty on the tackle, but it didn’t appear to be a helmet-to-helmet hit. Nor did Sanders appear to lose consciousness. However, NFL officials will take a look and determine whether to penalize him for a hit above the shoulders on a defenseless player.

Sanders was a free-agent signing during the offseason and has  been one of Peyton Manning’s favorite targets. Naturally, it wasn’t lost on anyone that the Rams’ defensive coordinator, Gregg Williams, is known for creating hard-hitting defenses. And for the suspension served for the New Orleans Saints’ bounty scandal.

It was a rough day for the Broncos, who also lost Julian Thomas and Montee Ball to injuries.