Thursday, 23 May 2013

Joey Bats Wins a Game by Himself

I was unlucky enough to be working during yesterday's late-afternoon Jays/Rays matchup, but I was following by the At Bat app on my iPhone (which is great by the way). It was surprising enough to see the Jays tie it up in the ninth, let alone win it in extras. That is a rare day in Toronto. It was only after checking out just how they won that I could not help but see that Jose Bautista completely dominated this box score. Whether or not it showed in the game is another thing, but I can't imagine you could walk away with any other impression.

4/4 With 2 HR and all 4 RBIs in a 4-3 win is good enough. A look at the Fangraphs WPA for the game though, tells just how crucial Joseph Bats was to the win. I know, I'm pretty excited about this baseball game and I haven't even seen a replay yet.

WPA stands for Win Probability Added, and it basically goes like this. At the beginning of the game, each team (theoretically) has a 50% chance of winning the game. They are tied at 0.500 to 0.500. Enough baseball has been played, over the course of history, that we are able to calculate for every possible game situation (inning/outs/baserunners/score/etc):
1) What is the probability that each team will win?
2) How much did the last thing that happen change that probability?

When the pitcher strikes out the first batter of the game, the pitcher's team is now slightly more likely to win - but just slightly. It is still a tie game and one team has 26 outs left, while the other team has 27. That was a low-WPA strikeout! The pitcher gets a small dose of +WPA, and the batter gets a small dose of -WPA.
Fast forward to the last out of a one run game. The closer strikes out the last batter with the bases loaded in the bottom of the ninth. That is a high-WPA strikeout! The closer gets a nice helping of +WPA, while the batter gets an equal and opposite helping of -WPA. Kind of like Newton's 3rd law, but for baseball.

A change of +1 indicates an entire win or loss. The WPA of all players on a winning team will add up to 0.500. The WPA of all players on a losing team will add up to -0.500. Generally, the more exciting the game, the more WPA that is given out (more lead changes, close finishes, etc).


That's where Jose comes in. Here's how his night went at the plate:
1. Bottom 1st, Rays 0 : Jays 0, 0 Out, Runner on 2nd.
JB singles in the run. WPA added = +0.07 (7%, from 61% to 68%)

2. Bottom 4th, Rays 2 : Jays 1, 0 Out, no baserunners.
JB HR to DEEP LF. WPA added = +0.13 (13%, from 43% to 56%)

3. Bottom 6th, Rays 2 : Jays 2, 1 Out, no baserunners.
JB Walks. WPA added = +0.04 (4%, from 54% to 58%)

4. Bottom 9th, Rays 3 : Jays 2, 0 Out, no baserunners.
JB HR to DEEP LF! Tie game! WPA added = 0.44 (An increase of 44% from 20% to 64%. Huge.)

Now the game is in extra innings, where runs scored by the home team are pretty important in determining who wins the game.

5.  Bottom 10th, Rays 3 : Jays 3, 2 out, runners on 1st and 3rd.
JB singles home the run and the Jays win. WPA added = 0.36 (36% added, from 64% to 100%)

Tonight, his total (b-ref) WPA was +1.053. That is the 39th best ever single-game WPA performance by a hitter. Ever. Here is the top 10 (thanks to baseball-reference):

Art Shamsky managed to get +1.503 WPA in only 3 plate appearances - kind of a big deal.
If you want to find out more about these games, there is a nice little summary here.

Jose also set the Blue Jays (batting) record for single-game WPA, smashing Robbie Alomar's 1991 record of 1.037 (when very few people knew that WPA was a thing). There have only ever been 8 Blue Jays with games over +0.800 WPA:

Coming into the game, Jose was carrying a cumulative +0.38 WPA this season. Now, his season WPA is a more robust +1.4. Needless to say, the Jays could use more games like this from The Boss (and others) if they are going to make a playoff push.

Pitchers get WPA scores too - equal and opposite to the hitters they face. Since the best thing a pitcher can do is get an out, pitcher scores tend to have more of a ceiling than hitters, unless the pitcher is pitching many shutout innings in a long extra inning game.

The highest WPA ever by a pitcher is 1.675, when Vern Law pitched all 18 innings in a 4-3 win in 1955. That sort of thing doesn't happen too much anymore.

The highest WPA by a pitcher in the last 20 years was 0.930 (Mike Magnate pitched 5.1 shutout innings in extra innings in 1996).

The highest WPA ever by a pitcher in a 9-inning game is 0.966 by Bob Keegan in 1956.

The Blue Jays record for WPA by a pitcher is 0.991 by Jesse Jefferson in 1980 for a 11 inning shutout.

So many fun facts!

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