I would sign them the worst player if competing or best player if tanking. The 2 year min idea is good though, stick them with an extra contract for the following season
2 year minimum and a cash fine are both ideas I like a lot but if you wanted to get even more extreme just treat it the same as a HC infraction. Your best player has to sit out the 1st sim, and if you’re a tanking team then your lotto odds drop or something.