Energy and overall confidence thing...
1) Lost to the Habs in epic fashion
2) Lost Hyman, Anderson, Thornton and was not able to improve the team due to cap
3) Most of the teams knows they might loose Rielly after this year
4) Forced to go with depth players in many areas of the line-up
5) Matthews starts the season on IR
They are top heavy with a few solid guys who can lead in the trenches (Tavares, Muzzin, Brodie). NHL is a coaching and team game and many teams have better depth than the Leafs. Shut down their PP and offense which can be done and their confidence is shattered.
Any team with grit, speed, and depth can beat the Leafs.
That Pittsburg loss is a clear example of that. I don’t even find the Pens all that speedy but they grinded the Leafs hard that game.