I've been having some fun this season analyzing Red Sox games with the Win Probability Graphs created over at
Fan Graphs.com.
Here is a good summary of how the graphs work from Dave Studeman of the
Hardball Times:
"Here's the basic idea. An average team, at any point in a game, has a certain likelihood of winning the game. For instance, if you're leading by two runs in the ninth inning, your chances of winning the game are much greater than if you're leading by three runs in the first inning. With each change in the score, inning, number of outs, base situation or even pitch, there is a change in the average team's probability of winning the game."
To take it up a notch, "Win Probability Added" (WPA) is the calculation the impact that each pitcher or batter has his team's victory (or defeat). For example, if a player hits a three run home run with his team up 15-0 in the ninth inning, he only helps his team's chance of winning by a small percentage because the win probability was already close to 100%. If the same player hits a solo home run with two outs in the bottom of the ninth inning with the score tied, he has had a huge impact on the probability of his team winning. The WPA statistic takes into account how well a player performs in the clutch. Fun, right?
Based on the season WPA statistics for the Sox, Jonathan Papelbon is actually the most valuable Red Sox player with a ranking of 211.7. Manny Ramirez is second with 171.3. The least valuable is Matt Clement with -90.2 with Alex Gonzales close behind at -84.4. Values are in percentages and every 100% equals one win.
The WPA season stats for the Red Sox can be viewed
here at Fan Graphs. There is also a great new site,
Sox Watch, where graphical WPA statistics are posted for every Sox game.
A side note about the Yankees WPA statistics: Even though A-Rod leads the team in home runs and RBIs, his WPA is only 10.9 (not clutch!) while Derek Jeter's WPA is 228.0 (super clutch!) Wow.
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