Okay I'm gonna take a crack at this...with explanations
Pastrnak: C- (Pastrnak has been decent offensively, but his zone entries and horrendous giveaways have come to light playing with Krejci, who isn't Bergeron. I'd give him a C, but he's on an expiring deal. At least he hasn't missed a game).
Zacha: B+ (Zacha has been better than I expected. Has created lots of offense and is a solid penalty killer when called upon).
Bergeron: A+ (I'm not explaining this one. The analytics (am I allowed to say that?) back this up).
Hall: C (He's really good at circling the offensive zone and sometimes scoring clutch goals, but it seems like no matter what line he's on he just go zoom zoom).
Lindholm: A- (Would have an A if he threw like one hit, ever. Pretty good offensively and in transition).
Coyle: A+++ (Well worth his contract. Hometown guy. Uses his body. Not sure I've ever seen him score a goal that didn't go in off a defender but the best 3C in the league on a value deal).
Nick Foligno: A (Wasn't sure about this guy, but his speed and puck protection have really shown us why we signed him).
Clifton: B (Meh).
Fredrick: A++ (When this guy drops the mitts I just about buy his jersey through Fanatics. Need more of his snarl on the roster. The analytics back this up).
Grzelcyk: A+++++ (Our best player this season based on the eye test. Real shifty, akin to how Adam Fox skates. Really good in his own end, and great in transition. My only gripe (would have 6 +'s) is that he's like 5 foot 8 or whatever).
Carlo A (Not sure how this guy only makes under 5 million green babes. If we trade him for Horvat i'd be a canucks fan).
Krejci: C (Shoot the dang puck).
Marchand: B+ (Would be a B if he wasn't funny on twitter. Kind of invisible 5v5 but at least hes good on special teams. Looks like he lost a step, I wonder if he's gone after this season).
Nosek: A (He used to skate like he had cement in his skates. Now he skates like he doesn't have cement in his skates. Good faceoff taker! A little injury prone though, or else he'd be A+).
Derek Forbort: A+ (Great PKer, and he's big and blocks shots and sometimes hits. What more could you want on a 3rd pair guy).
McAvoy: B- (He looks like he just got his 9.5 milly and is afraid to take a hit. Not sure what's going on there. Throw that thick body into an opponent, will ya!).
Smith: B- (Scored a couple goals recently. I think he's on the up and up. Give it a chance).
Greer: A (Does what he's asked. Chucks the Knucks and is a good ol boston boy, at least in college. Could see him helping us with a deep playoff run, we need bruisers with snarl like him. Analytics back it up too.).
Zboril: D (Another Sweeney 2015 bust. His play is a reflection of how that draft went as a whole (made the NHL but stinks!!!) Hope we get some spare parts or a bag of pucks for him soon).
Stralman: ??? (To be honest I've never heard of Strallman. Not really sure where he is right now.)
McLaughlin: D+ (Go back to providence.)
Koppanen: A+ (Perfect nosek replacement when called upon. Will be a great black ace to help us against teams like tampa down the stretch. Big body, likes to rough it up physically).