Win Probability Added (WPA) is defined as the difference in Win Expectancy between the start of the play and the end of the play. Basically, WPA assigns value to how much a specific at-bat helped or hurt the team's chances of winning at that moment. The higher the leverage, the more value assigned to the particular at-bat. For example, there is much more WPA to be gained or lost for a player batting down 1 run in the 9th than if the same outcome occurred while up 6 runs in the 4th.
Most of you have seen the Win Expectancy graphs from Fangraphs posted here in game threads or recaps, but on the off chance that you haven't: they look like this. All these charts do is add or subtract the WPA for each play to determine how likely a team is to win the game. They are helpful if you want to see how much one specific play changed the game, or which player added the most to a win based on their calculations. Sometimes they fluctuate wildly, other times they are more of a steady progression, depending on the scoring in the game.
Now that the explanation most of you likely didn't need is out of the way, onto the actual point. I decided to look at each Yankee game of the 2011 season to find the 10 individual offensive plays with the highest WPA. No small task, I assure you. Most aren't that surprising, but it's an interesting look at the individual plays that had the most statistical impact on a game throughout the season. If you'd like to see a players total WPA for the 2011 season, Fangraphs keeps track of that here.
Beyond the jump you will find the list of what WPA says are the top 10 plays, but first, there will be a graph. Of course.
After looking through each game's play log to find the at-bat worth the highest WPA, this is what I came up with:
Stats via fangraphs.
The graph represents the number of games throughout the 2011 season that each batter had the play of the game worth the most WPA. No real surprises here, except maybe where Alex Rodriguez falls among the starters despite missing a good chunk of time with injuries. He has the benefit of great power, so perhaps it's not that surprising after all.
Interestingly enough, in 14 games for the Yankees, a walk, hit by pitch, or error by the opposing team was the play with the highest positive WPA for them for the game. Knowing how immediately a home run can change a game, it should surprise no one that 68 games had a home run as the highest positive WPA play by a Yankee.
Now, that list I promised. The top 10 offensive plays of the season according to Win Probability Added:
10. September 17, 2011: Curtis Granderson's 7th inning 2 run home run off Carlos Villanueva. (.300 WPA)
Situation: Down 1 run before the HR. Yankees go on to win 7-6.
Situation: Tie game before the single. Yankees go on to win 5-3.
8. July 18, 2011: Russell Martin's 9th inning bases loaded walk off Alexander Torres. (.330 WPA)
Situation: Tie game before the walk. Yankees go on to win 5-4.
7. September 1, 2011: Russell Martin's 7th inning 2 run double off Daniel Bard. (.336 WPA)
Situation: Down 2-1 before the double. Yankees go on to win 4-2.
6. August 11, 2011: Robinson Cano's 7th inning grand slam off Scott Downs. (.343 WPA)
Situation: Tie game before the home run. Yankees go on to win 6-5.
5. September 11, 2011: Mark Teixeira's 7th inning 2 run "sac fly" off Scott Downs, botched by Peter Bourjous. (.362 WPA)
Situation: Down 5-4 before the sac fly and error. Yankees go on to win 6-5.
4. May 24, 2011: Curtis Granderson's 9th inning RBI single off Frank Francisco. (.396 WPA)
Situation: Down 4-3 before the single. Yankees go on to win 5-4.
4. May 11, 2011: Curtis Granderson's 10th inning RBI single off Joakim Soria. (.396 WPA)
Situation: Down 3-2 before the single. Yankees go on to lose 4-3 in the 11th.
3. September 3, 2011: Robinson Cano's 7th inning 2 run double off Casey Janssen. (.404 WPA)
Situation: Down 4-3 before the double. Yankees go on to win 6-4.
2. April 14, 2011: Jorge Posada's 9th inning home run off Kevin Gregg. (.429 WPA)
Situation: Down 5-4 before the home run. Yankees go on to win 6-5 in the 10th.
1. August 25, 2011: Russell Martin's 6th inning grand slam off Fautino De Los Santos. (.443 WPA)
Situation: Down 7-6 before the home run after coming back from down 7-1. Yankees go on to win 22-9. Oh.
So, there you have it. Big home runs and coming through when the game is late and close (clutch!) will land you on the WPA leader board for the season. It's extremely likely that none of these plays will really be remembered in the future. People won't talk about them when someone brings up the 2011 season the way that they will Derek Jeter's 3000th hit or Mariano Rivera breaking the saves record, but they had a strong positive correlation to getting a win for the Yankees, and that is always the goal.