Description:
Most sabermetric statistics are context neutral, meaning they disregard the
fact that during the course of a game some plays are more crucial than
others. While wOBA rates all home runs as equal, we know intuitively that a
home run in the third inning of a blowout is less important than a home run
in the bottom of the ninth inning of a close game. Win Probability Added
(WPA) captures this difference by measuring how individual players affect
their team’s win expectancy on a play-by-play basis.
For example, if we were to take a specific game, say the Rays have a 45%
chance of winning before Ben Zobrist comes to the plate. During his at bat,
Zobrist hits a home run and the Rays’ win expectancy jumps to 75%. That
difference in win expectancy (in decimal form, so +.30) from the beginning of
the play to the end is Ben Zobrist’s WPA. If Zobrist strikes out during his
next at bat and lowers his team’s win expectancy by 5%, his overall WPA for
the game would be +.25.
定義: 球員的每個play對球隊勝率的貢獻加總，某種程度上可視為是關鍵能力的展現 (?)
Name WPA Name WPA
Ian Kennedy 5.23 Jose Bautista 7.61
Justin Verlander 5.16 Joey Votto 6.71
Jered Weaver 4.85 Miguel Cabrera 6.33
Roy Halladay 4.71 Prince Fielder 6.09
Cliff Lee 4.47 Matt Kemp 5.58
Cole Hamels 4.19 Josh Hamilton 5.25
James Shields 3.98 Jacoby Ellsbury 5.22
Dan Haren 3.95 Lance Berkman 5.1
Josh Beckett 3.92 Ryan Braun 5
Clayton Kershaw 3.83 Albert Pujols 4.34
Ricky Romero 3.8 Ryan Howard 3.94
CC Sabathia 3.54 Adrian Gonzalez 3.66
Shaun Marcum 2.68 Carlos Beltran 3.52
Tim Lincecum 2.52 Alex Gordon 3.5
Johnny Cueto 2.42 Bobby Abreu 3.26
Randy Wolf 2.27 Curtis Granderson 3.15
Justin Masterson 1.97 Aramis Ramirez 3.08
Joe Saunders 1.96 Hunter Pence 2.99
Ryan Vogelsong 1.96 Evan Longoria 2.95
C.J. Wilson 1.9 Shane Victorino 2.93