Other than pending labor strife, the biggest issue that exists between the league and the players is the issue of big hits, concussions, and the treatment of both the perpetrator and the injured following those concussive hits.
The NFLPA held a press conference yesterday on the eve of the Super Bowl in order to weigh in on a number of topics, and one of those discussed was just that. Union Executive Director DeMaurice Smith made clear that it was the responsibility of both the league and the players to curb those sorts of acts from the game.