There are a number of reasons why the Leafs seem to be routinely coming up short when the games matter most. A lot of these reasons relate to the salary cap and how they've elected to construct their roster. However, their one main roster flaw is their lack of a true #1 defenseman who can eat a ton of minutes and play in all situations.
Now, I know that many will rebut with "Morgan Rielly is our #1 defenseman", and you're not entirely wrong. He is our #1 defenseman. But he's not on the same level as some of the other #1 defensemen around the league. In fact, if you were to take Morgan Rielly from the Leafs and drop him in Vegas, he's very likely a #2 or #3 defenseman, behind Alex Pietrangelo and perhaps even Shea Theodore.
On Wednesday, Sportsnet's Drew Livingstone took a look at each the last 17 Stanley Cup winners and who their top defenseman was for each winner. The list may actually surprise you.
2023 - VGK: Pietrangelo2022 - COL: Makar2021 - TBL: Hedman2020 - TBL: Hedman2019 - STL: Pietrangelo2018 - WSH: Carlson2017 - PIT: Letang2016 - PIT: Letang2015 - CHI: Keith2014 - LAK: Doughty2013 - CHI: Keith2012 - LAK: Doughty2011 - BOS: Chara2010 - CHI: Keith2009 - PIT: Letang2008 - DET: Lidstrom2007 - ANA: Niedermayer
The answer to the problem seems somewhat simple now. The Leafs cannot continue to allocate so much of their cap space to 4 forwards. It's no coincidence, when you look at this list, that a true #1 defenseman is a pretty substantial part of a winning organization. There's not one single name on this list that you could have traded Morgan Rielly in a 1-for-1 deal.
The solution seems like a relatively simple one here. The Leafs just need to find a way to parlay one of their core forwards into a top defenseman via trade. I get that it's easier said than done, but if you're looking at this list of Stanley Cup winners and their defensemen, it's a pretty clear indication that a top defenseman is exactly what the Leafs are missing.
Since the Leafs obviously aren't going to trade Auston Matthews and they can't trade John Tavares due to his NMC, the two remaining options are Nylander, a 40-goal scorer, and Marner - a 3-time 90+ point player.