I would somewhat disagree, and I do have an understanding of employment law. Their obligation is to pay him, not to play him. I can't imagine an environment where the NLPA could influent usage or ice time and that's really what this would boil down to. How many minutes he plays and with who is not going to be written anywhere in his contract so there really isn't a basis to grieve. If there is a section in the NLPA that specifically relates to allowing the player in games I am not aware (if you have it please provide the link but I am too lazy to hunt). Unless he had a game related bonus that was going to cost money of course but those are almost non existent.
IMO flat out sitting him would create a toxic environment and morale issues with the team and thats why benching him for no reason until he submitted to being dealt wouldn't be considered.
Everything below is
IMO / pure speculation ... I'm not legally trained but I have watched L&O since the beginning of time.
Not playing him would result in a grievance, and given the evidence the Leafs would lose.
There would be no justification for a complete benching.
On and off ice performance could not be used, as his record places him near the top of the NHL.
Unless there is some dirt no one knows about the only reason Leafs could provide was they want him to waive his NMC.
That would not be, IMO, as valid reason since both the team and the player agreed to the NMC.
Taking it further, you could argue that is an attempt to breach the contract by the Leafs.
I suppose the judgement could be voiding the contract and making him a free agent.
Maybe that outcome would suit a group of fans?
What they could do however is limit his usage.
Easily justify they are trying to improve a weak PK.
PP is near the top in regular season, but brutally bad playoffs.
Playing on the 3rd. or 4th. line is to spread out the offence.
Again my opinion:
I don't think either scenario is going to happen, or would make any sense.
The goal is to win, not force players to abandon their contractual rights.
marner in the line-up being deployed to get the most out of him is the only logical scenario.