I'm really flabbergasted that people actually think it's a good idea to trade our #2 defenseman on an already weak defense. You don't trade an elite defender in his prime on a great contract like Muzzin
Forbort is fine with Doughty, Martinez is fine on the second pair and plays better on the left. There is no reason to have Muzzin on the 3rd pair. Move him and grab a shutdown RHD.
We learned last playoffs, when Martinez went down that Muzzin is incapable of carrying a defensive pairing because he can't move the puck out of the D-zone. Muzzin needs to be paired with a puck moving defensman. Which means he's playing with Doughty, Martinez (on his off side), or maybe LaDue in a couple of years. Then LaDue if/when he makes the jump will probably not be playing 15+ mins so there's no one to pair Muzzin with. Well Doughty, but Doughty doesn't need him.
You could move Martinez instead of Muzzin. That would mean you need a puck moving RHD to pair with him, which is harder to find then a shutdown guy to pair with Martinez.
You could just run Muzzin/Martinez. What we saw from the 2 being split apart was that there wasn't a significant drop in play from Muzzin/Martinez to Martinez/Greene. Now Greene is going to run into trouble logging 17-20 mins a night. lol... but it shouldn't be that hard to find a shutdown top 4 RHD. Also the Muzzin/Martinez is a fine patch and you can get by on that. Come playoff time when advancing to the next round can come down to a deflection/bounce in OT Martinez playing his offside could make that difference. Best to minimize the errors.
More or less the Kings don't need Muzzin. Forbort's ability to move the puck makes up for any edge on defensing that Muzzin might have. So grab a shutdown RHD that can play top 4 and move Muzzin. Didn't Forbort have like a 75% Corsi at some point?
As this is a development year and I doubt Lombardi will do anything at the deadline other then add a cheap vet (VL/Schenn), moving Muzzin before the expansion draft wouldn't make a lot of sense, unless some contender threw a rediculous offer out there. Most of the deadline deals are picks/prospects so it would have to be something really special. Other then that hold on to him until after the expansion draft when teams are looking to fill holes that have been caused by the draft.
Also I reject that Muzzin is the 2nd best D. If you're talking about leaving the defensive zone he's right there with McNabb at about 4-5. That can drop too if Gravel breaks out.
Edit: Comes down to it's harder/more expensive to find Muzzin a right handed partner then Martinez. Also Sutter benched the hell out of Martinez in order to teach an offensive defensman to be defensively sound. Even if you were able to land a Barrie type defender to pair with Muzzin, Sutter would have his work cut out for him teaching that player how to play defense. Martinez is more valuable to the team because of his transition game and being harder to replace.