You don't bring a young D who you believe has high potiential into the lineup without a proper partner to mentor them and a proper role to strive towards. The same goes for Liljegren. This isn't supposed to be some future bottom pairing D. The Leafs' knew as much last summer when Dubas said that Sandin and Liljegren were not going to play and therefore they had acquired: Schmaltz, Gravel, Harpur etc, on top of already having Marincin to fill in for injuries. If you find you need more during the season those type of replacement level Ds are easy to acquire. That was the correct plan.
In Sandin's first 6 game stint he had 5 shots and 11 shot attempts.
In his second stint over the first 11 games he had 13 shots and 28 shot attempts.
In his second stint over the subsequent 11 games he had 4 shots and 9 shot attempts.
By comparison Marincin played fewer minutes this season, and played those minutes in a more defensive role, but had more shots and shot attempts than Sandin. (71 shot attempts vs 48).
And this sticks out like a sore thumb if you go back and watch all the games. Sandin completely loses his confidence to create offensively and stops playing anything that might resemble his game.
When you bring in a young D with a lot of potential you get him a proper partner. Think of Barrie and then look for the exact opposite D in basically every respect. You want him to have the confidence in his partner that he can take chances offensively and see where his limits are. You get him playing in as many situations as possible. You build him up to play against better competition. You get him on the 2nd PP unit even if means playing 2 D.
John Carlson who had near identical AHL production, WJC results, and played about the same amount of games and minutes in the NHL in his first season as Sandin did, at the same age. Was playing 20 minutes a game come the playoffs that year, and was a first pairing D the next season, and played on the Caps 1st PK unit for his first 5 full seasons in the NHL. Rapid development and massive gains in confidence which should be happening with all young D that age. Not the opposite as has been the case with Sandin, or the 3 years of ridiculously sheltered third pairing stagnation with Dermott until they finally gave him a shot at more when they had no other choice.
Look at what the Bruins have done with McAvoy and Carlo, the Avs have done with Girard and Makar, the Canucks have done with Hughes, the Hawks have done with Boqvist, etc.
*I was unaware of Kyle's comment that Sandin and Liljegren were not going to play. I agree that replacement level players can be easily acquired. I mentor is a great thing to have.
*I can't really comment on 'Sandin's game'. My knowledge of him prior to playing with the Leafs is only based on what I read. I don't follow the Marlies from where I live. That said, would I be correct in saying that those you listed, Schmaltz, Gravel, Harpur etc, did not have successful seasons with the Marlies and that given the dogfight the Leafs were in to make the playoffs, Sandin (2nd stint) was the obvious choice to call up? If memory serves, Sandin was used after both Rielly and Muzzin were on the shelf. A high danger move, to be sure, if you are looking to put the kid into a safe position for success.
*While a D partner the opposite of Barrie would be ideal (thinking Van with Hughes and Tanev) we haven't had that type of mentor since Hainsey for Rielly, Mo of course having far more experience than Rasmus. It's the most glaring hole in the Leafs arsenal and neither Lou nor Kyle adequately addressed this need.
*I appreciate the comparisons to Carlson and the others, I'm not sure I have the confidence you do in seeing them as comparable. In Carlo and Carlson you have two D who have much larger frames to help insulate them from the demands of the game as well as being integrated with far more mature D corps. In Hughes and Makar you're asking to compare Sandin with two of the more dynamic young D to enter the game in many a year, a large ask. Boqvist, I've not seen play, but he and Girard might be the closest?
*Like you, I would like to have seen Dermott moved up.
You've put forward a persuasive case. I'd earlier suggested seeing Sandin put in before Marincin. You've changed my mind. I don't wish to see his confidence blown, and that is a worry, as you've outlined. However, I'm hopeful that you're initial comment about 'ruining?' (my memory here may be faulty) his development may be a touch premature. Sandin and Liljegren both deserve stable partners to work with if they are going to join the Leafs next year. How that shakes out, time will tell. Enjoy the game tonight.