Pro Football Talk's Mike Florio reports that the NFL will review the post-game altercation between 49ers head coach Jim Harbaugh and Lions head coach Jim Schwartz. Greg Aiello, an NFL spokesman, told PFT that a "key issue" will be if any physical contact was made. If there was contact between the coaches, the NFL will examine how severe it was before deciding the next course of action.
From watching the video of what happened, it seems like Harbaugh and Schwartz only had contact twice: when they shook hands and when Schwartz bumped into Harbaugh after chasing him down (the first time). Perhaps Schwartz could be fined for bumping into Harbaugh, or perhaps Harbaugh could receive a punishment for his over the top handshake.
To me, neither scenario seems likely. My guess is the NFL will contact both coaches and reprimand them for their conduct after the game. I wouldn't be shocked if a fine was given out, but to me a stern warning to not let it happen again seems like the course of action the NFL will take.
The funny thing if either coach is actually punished is that what happened created a whole lot of buzz for the NFL. It's not like they need it, but what happened between the two coaches didn't take anything away from the game of football. In fact, if anything it created a very intriguing storyline and potentially a new rivalry if the two teams meet in the playoffs.