I used Hockey Reference's point share system* to attempt to take stock of where the Leaf's roster was headed:
The following players' contributions were removed from the Leafs' 2008-09 season:
Kubina 5.2
Antropov 4.3
Goaltenders 2.9**
Stempniak+ 1.9***
Stralman 1.6
Hamilton 0.6
Enforcers -1.3****
Total: 14.9
And they added the following players:
Kessel 8.8
Gustavsson 8.4*****
Beauchemin 4.5******
Komisarek 2.8
Stempniak 2.8***
Exelby 1.0
Primeau -0.2
Orr -0.7
Total: 27.4
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That amounts to an expected increase of 12-13 points, giving the Leafs enough to sneak into the playoffs.
Obviously, that's not what happened. If we're assigning blame, here are a few players who dropped like a rock between the two seasons:
Mike Komisarek: From 2.8 to 0.2
Jason Blake: From 6.2 to 2.0
Vesa Toskala: From 6.0 to 1.2
Those three players nearly wipe out the "expected" increase by themselves, while Gustavsson and Kessel "cost" the Leafs 5 or 6 points by not being immediate, franchise-altering world-beaters (who could blame them).
Point shares might not be a fantastic stat, but these numbers look pretty similar to how we all saw it play out.
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* Which isn't good, but I can't access GVT right now, and I may as well use something for the fun of it.
** Total of Gerber, Joseph and Pogge, mostly from Gerber.
*** Departing is the total of partial seasons from Stempniak, Steen and Colaiacovo. Incoming is Stempniak's total extrapolated to 82 games.
**** Total of Hollweg, Ondrus and May. Ugh.
***** Expectation based on the median of rookie goaltenders who played at least 30 games between 2005-2014. Incidentally, this number belongs to Fredrik Norrena.
****** From 2007-08, as Beauchemin missed most of 08-09 with injury.