While it technically meets all the elements of criminal assault, and I don't think a consent defense would work (as opposed to a hard hit in the course of play), the chances of criminal prosecution are extremely low. The main reason is just historical precedent - it never happens. The only example I'm aware of was the Pistons-Pacers brawl at the Palace, which resulted in criminal assault charges against several players. That incident is slightly different because it also involved a fan, an usher and some other non-players.
"Bertuzzi was charged with criminal assault causing bodily harm. He pleaded guilty and was sentenced to one year probation and 80 hours of community service."
"McSorley was found guilty of assault with a weapon and was sentenced to 18 months probation."
"Ciccarelli was charged and convicted of assault. He was fined $1,000 and sentenced to one day in jail."