Nashville is screwed eight ways from Sunday if he retires, Montreal much less so.  This article spells it out: 
 
	https://www.msn.com/en-us/sports/nhl/the-salary-cap-implications-of-a-shea-weber-early-retirement/ar-AAzKrlW
 
	I'd imagine he uses the Pronger loophole (assuming it remains available) and just rides it out on LTIR under suspicious circumstances when it's time.