The Leafs have so many players, and so few roster locks, it's hard to really have a strong idea. Here's my best shot:
James vanRiemsdyk - Nazem Kadri - Leo Komarov
Nikita Soshnikov - Tyler Bozak - Mitch Marner
Brendan Leipsic - Auston Matthews - William Nylander
Matt Martin - Peter Holland - Zach Hyman
Jake Gardiner - Connor Carrick
Morgan Rielly - Nikita Zaitsev
Martin Marincin - Frank Corrado
Frederik Andersen
Jhonas Enroth
I'll just start by saying that I think given reports out of Sweden, there's a good chance Enroth becomes official whenever the Leafs' cap situation is worked out. I don't know if this is a trade situation, or they'll have to give him a camp invite and sign him once someone's on LTIR, or maybe the Cowen buyout eventually goes through somehow, idk.
So, JVR/Kadri/Komarov did a good job together possession-wise, and I think they maintain that as the top line for some semblance of stability. Babcock said at the draft that they had Matthews on the third line to start the year behind Kadri and Bozak. I'm a little skeptical, but I'll grant him that. I wonder if Nylander and Marner switch centers one way or the other, because Nylander is a slightly more pass first guy, and Bozak really needs a distributor, but it's possible Marner will shoot less/pass more now that he's out of junior, himself. So, we'll see. I'm tempted to switch Martin and Leipsic, because Leipsic ain't a liability defensively, but he's not a defensive conscience. Babcock likes to have a defensive guy/play disruptor, a distributor, and a shooter on every line. Komarov is the disruptor on line one. Soshnikov on line two. Line three, Matthews projects to be good defensively, but he'll be 19. Leipsic is a bit of a pain in the ass, but idk if he's gonna be that guy. Meanwhile, the entire fourth line of Maritn, Holland, and Hyman can play that role, so I could see them switching Leipsic and Martin from what I have, and give a better offensive player to Holland/Hyman, and a better defensive player to Matthews/Nylander. There are other complications here, too. Leivo requires waivers now. But there's also a point where you wonder when he's ever going to fit. I think he's gonna be a 20 goal, 35-40 point guy, a real useful depth scorer, but he hasn't shown enough to get back a real asset, and the team is just so deep with futures right now. He may just be gone. Connor Brown is gonna push for a spot on the right side, and I gave it to Hyman because he's older. Then there's Kerby Rychel, who may even overtake Leipsic, just because his issues in Columbus were opportunity related, and they did go out and trade for him. Hard to see him in the AHL. Babs also isn't Holland's biggest fan, so I could see him as the thirteenth forward, Hyman moved back to center, and Brown on their right wing, in which case, I'd think that makes Martin staying on the fourth line more likely, given Hyman is tall but lanky, and Brown is small, they might wanna balance the size. I personally think Leipsic is a guy who can be a real solid second line winger, and Rychel is probably more of a decent checking third liner. Sorta the difference between... I don't know, Darcy Tucker and Chris Neil, I guess.
As for the defense, Babcock also likes to balance defensive pairings. Given the ice-time allocation from last year, I expect Gardiner is the top LHD, Rielly second, and Marincin third. Marincin and Corrado are very defense-offense balanced. They also, in a limited sample, really caved in opponents in terms of possession. Gardiner and Carrick also did really well together, although to my eyes, they both look pretty good both ways. Rielly and Zaitsev present a problem. Zaitsev is obviously very smooth offensively, but given how much spacing matters in defensive play, I wonder how the smaller ice changes things. If he's not strong defensively, there's nobody to balance just how weak Rielly is defensively. I have faith in his right now, but I'm not the world's biggest fan of Rielly, and if Zaitsev can't cover for him, they'll probably end up on the bottom pairing. Given the roster, and Shanahan's comments about Polak being "more of a depth guy" rather than "a solid number five or six" when they got him the first time, I think one of Hunwick or Polak sits in the press box, the other goes to the Marlies.
I've also left out Greening, Michalek, and Laich. Here's the deal there: I think they try to dump all of them at the soonest possible point, and I'm not really convinced they have the off-season they just had (signing Martin, getting Rychel, pushing hard for Vesey, etc) if they're supposed to play regularly. I could see Greening and Laich being in the lineup over Leipsic/Holland on opening night. But I just can't see any of them going the whole year without being waived, demoted, or traded. Maybe Greening. Had good possession numbers in Toronto, Babcock seems to like him. Idk. Again, this is really difficult, I think there'll be a hundred Leaf posts ITT and nobody, myself included, has much of an idea what we're on about. Maybe the Leaf forum should have some sorta contest to see who can name the most players in the opening night lineup. Then they'll sign Brad Boyes or Jiri Hudler and we'll all be screwed.