The faking of an injury has been going on for a long time. It really shouldn’t be allowed. But, how do you enforce a penalty on this? How do you prove on is injured or not? I think if you try to penalize something like this, it could lead to more problems.
“During Sunday’s Raiders-Broncos game, an Oakland pass along the sideline was ruled a completion, but Denver thought the receiver failed to get both feet inbounds. The Broncos wanted to have time to check the replay and throw the challenge flag as the Raiders were lining up to run the next play, so Broncos linebacker Von Miller did the one thing a player can always do to get the officials to halt the game: He said he was injured.” – Reported by Michael David Smith
More here: NFL morning after: League should crack down on fake injuries