If the police interview the accused and he explains that he was trying hit Johnson, but prior to contact he got impeded by another player and in the process of falling he wanted to stick his leg out there to get a piece of Johnson to slow him down. Technically a penalty but something that guys do all the time in the course of a hockey game, often going uncalled. Would that be enough for a Manslaughter charge to stick? He had the intent to make contact with with Johnson with his leg, but obviously no intention of contact with his skate blade, or with Johnson's neck area.
I think that's as far as this could be reasonably argued. He stuck his leg out there to impede him with horrible consequences because of how off balance he was. If he admits that much would that be enough to meet manslaughter requirements?