He should be suspended for the rest of the season.
Hockey players are the only pro athletes that are essentially armed with knives during competition, and the NHL needs to make a statement that actions like that are dangerous, especially when even just an accident with a skate can severely injure someone (like Clint Malarchuk).
I was going to come in here and say for the rest of the season too. Obviously Simon didn't learn anything about sportsmanship in his 25-game suspension. Even as a first time offense, something like this should have quite a large punishment; if they weren't on the ice in a game it could be considered assault with a deadly weapon