The story of League's transformation in 2009 and reversion in 2010 has been well documented throughout the entire season. As such, I do not feel a need to burden you with a recap. Instead, with the conclusion of 2010, I can now update the comparison that I made at the end of July looking at League's two primary pitches.
2009 Fastballs - 5% whiff rate, 66% strike rate, 51% ground ball rate
2010 Fastballs - 8% whiff rate, 64% strike rate, 59% ground ball rate
By and large, the fastball was more successful for League this season. That might have been part or the whole of why he threw it so more often. If so, it's still not a great strategy. What it helps with reducing walks, and League's walks did fall this year, it does nothing to help his strikeout or ground ball rates.
2009 Splitter - 35% whiff rate, 59% strike rate, 61% ground ball rate
2010 Splitter - 26% whiff rate, 51% strike rate, 64% ground ball rate
These are very small samples, but it does appear that League was less successful at getting hitters to swing after his split-finger this past season. Whether because he used it less or because something about the way he threw it made it less enticing is difficult to prove. I can say that based on pitch f/x, the movement of the pitch didn't change much.
2010 League did keep more balls on the ground which is good, but we were expecting a lot more in the strikeout aisle of the reliever store. Ultimately, League turned into a decent enough performance this season. He was burdened with much higher expectations though and I cannot shake the feeling that simple pitch selection was the biggest fence to reaching those.
If Carl Willis is retained as the pitching coach for next season, I don't have much hope that the impetus to revert back to 2009 will be handed down to League and I doubt League makes the leap himself. Over and over again we've seen pitchers fall in love with their fastballs to the exclusion of better offspeed pitches. Most of them required outside assistance to modify those habits. I sure hope someone from the front office is peeved enough about not getting the League they thought they were getting to make some noise on the field level. It may be our only hope.