New York Yankees: Win Probability Added
July, 29, 2012
By Mark Simon, ESPN Stats & Information
Getty Images/Jim RogashMark Teixeira's high-fives this month have been well-earned.
There are a number of players who could make a case for being AL Player of the Month for July.
But Mark Teixeira might have the best argument.
Teixeira not only has a major-league-leading 27 RBI for the month, one in which he’s hitting .329 with seven home runs (including yesterday’s, which made him the sixth player to hit 20 home runs in each of his first 10 seasons), he’s also provided the most offensive value by way of one advanced baseball number.
Sabermetricians like a statistic called “Win Probability Added.” For those unfamiliar, Win Probabillty Added (known as WPA) measures the importance of everything a player does.
It’s a point-scoring system, with players earning points based on doing positive things (getting a hit, walk, hit by pitch, reaching on an error) and lose points for doing negative things (making an out). The more important the situation (based on the inning, the score differential, and the number of men on base), the more points a particular play is worth.
For example, Teixeira’s game-tying home run against Vicente Padilla on Saturday took the Yankees from a position in which they had a 13 percent chance of winning the game to a 53 percent chance of winning the game. Teixeira gets a bump of 0.4 points for increasing the Yankees chance of winning by 40 percent.
Both Baseball-Reference.com and Fangraphs track Win Probability Added, with Fangraphs offering month-by-month splits in leaderboard form. With three days left in the month, Teixeira has been worth 2.26 “Wins Added” in July. The next-closest player is Josh Willingham of the Twins at 1.64.
A 2.26 month in this stat would be very impressive by Yankees position player standards. Over the last 10 seasons, the only Yankees hitters to rate better than a 2.00 for a month are Jason Giambi (2.45 in June, 2003) and Gary Sheffield (2.23 in August, 2004)
How does one get such a high rating? Take a look at the chart on the right, which lists the highlights from Teixeira’s July.
Statisticians take the WPA stat one step further by assigning what they call “leverage” to each situation. The most significant situations in a game (ie: the ones where a team’s chance of winning can swing the most) are known as high-leverage situations.
All of the hits listed in that chart were in high-leverage situations. How much better was Teixeira in high-leverage situations this month than the previous three? Consider this.
Teixeira has 10 high-leverage hits in July (we didn’t list all of them, but you can see the list here). From April to June, he totaled 11.
Looking ahead to tonight’s matchup, Teixeira will have a chance to pad his Win Probability Added total against a pitcher with whom he’s quite familiar. He’s 2-for-6 against Felix Doubront this season with a pair of home runs.
There is one other mark at which Teixeira can take aim.
His 2.26 is not the best WPA for the season. He probably needs another signature moment or two to catch the leader- Giancarlo Stanton, who posted a 2.73 WPA for the Marlins in May.