It should be a 1 or 2 game ban at most. There was no contact to the head which means it wasn't horrendous, but it's not just shoulder charges to the head that are banned, it's all shoulder charges. They're banned because they carry an unacceptable risk of injury to players.
If you trip someone you get a ban, if you make a canonball tackle you will probably get a ban (and definitely will if you injure someone), same for a high tackle, same for any other dangerous contact charge. Injuries are aggravating factors for disciplinary matters. So if you make a shoulder charge and it results in injury, it would be ludicrous to not be at risk of a ban.