The NFL Player's Association has announced that they, along with the NFL, are reviewing the Patriots' handling of safety Patrick Chung's concussion. 

Chung appeared to be shaken up on a run play early in the second quarter. He left the game, but returned after only one play. He remained on the field until the end of the first half. The team announced he would be out for the reminder of the game after the team came out of the locker room. 

The decision to let Chung back into the game was a medical one, not a coach's decision, as Bill Belichick reiterated when asked about Chung on a conference call Tuesday morning. The NFL has independent doctors on the sideline for situations exactly like this. If they determined Chung should be checked for a concussion, then he wouldn't have had the option to re-enter the game. 

As it stands, it appears that both team and league officials determined that Chung didn't need to undergo concussion protocol, and was cleared to play. During halftime, something changed their minds, Chung underwent concussion protocol and did not return to the field. 

The league review is simply ensuring the Patriots went through the correct procedures in handling Chung's situation. From an outside perspective, if Chung re-entered the game with a concussion, it falls on the shoulders of the league and team doctors. The Patriots were told he could re-enter the game, so they sent him back in. The results of the review will determine if the league, and the Player's Association, think otherwise.