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Friday, June 09, 2006
Walking Bonds with the Bases Loaded
Barry Bonds was intentionally walked with the bases loaded, a 2-run lead, in the bottom of the ninth, and 2 outs on May 28, 1998. Was it a good play or not?
Here’s the boxscore, courtesy of Retrosheet:
http://www.retrosheet.org/boxesetc/B05280SFN1998.htm
According to Leverage Index (LI), the most crucial situation is the bottom of 9th, down by 1, 2 outs, bases loaded. When Showalter walked Bonds, he did so to present his pitcher with the worst possible situation. The LI jumped from a 7.0 to a 10.9. (Remember, the average LI is 1.0.) That is, he made the game state situation 56% more difficult for his pitcher, in return to face a player who produces much worse than Bonds.
Let’s say that Bonds is typically +.11 runs above average per PA against righties. Brent Mayne, a lefty, was 30 years old, and at that point in his career, was a slightly below average hitter, which make him about an average hitter against righties. Let’s make Mayne +.00 runs per PA.
The pitcher was Gregg Olson, who from 1997-1999 had 134 K and 71 NIBB facing 764 batters. Close enough to league average that we can use the standard win probability numbers. (Even if he wasn’t, that both hitters are facing the same pitcher helps our analysis anyway.)
When you have an average situation, the LI is 1.0, and the runs per win (RPW) is 11.0. If the LI is 2.0, the RPW is 5.5, etc.
Bonds’ +.11 runs per PA translates to .11/11 wins (.010 wins per PA) when the LI is 1.0. In this case, he was at 7.0, making his win impact at .010*7= +.07 wins.
On page 41 of the book, we see that the win probability of the bases loaded, 2-run, bottom ninth situation is .182, if all participants involved were league average players. However, we have Bonds at bat. And in this situation, his impact is +.07 wins. The Giants’ win probability is really .252 with Bonds at bat.
Now, Showalter walked him to face an essentially league average hitter. The win probability table shows us that the chance of winning for the Giants is now .283. So, by walking Bonds, the Giants’ chances of winning increased by about +.031.
Is that alot or a little? Consider that a good hitter is around +20 to +25 runs per 600 PA. This is about +.33 runs per PA, or +.03 wins per PA. So, +.03 wins is definitely alot.
However, how much margin for error do we have here? Let’s say that Showalter believed, for whatever reason, that Bonds was not +.11 runs per random PA, but was +.12. And that Mayne was not +.00, but -.01 runs per random PA. Giving the benefit of the doubt of .01 runs per PA is something that I can reasonably grant the manager. There could be variables at play that could nudge things around. How do the win probabilities change?
Bonds’ +.12 runs per PA becomes +.076 wins, which turns the .182 win probability for an average hitter to .258.
With Mayne’s -.01 runs per PA, that’s also -.01 wins per PA. Remember, the leverage here was the highest possible 10.9, and we have 11 runs per win. Essentially, a run is a win. So, with the chance of winning at .283 with an average hitter, it becomes .273 with Mayne. It still would have been better to have Bonds batting, and not Maybe, with the win gain down to +.015.
When does it become a breakeven point? If we grant the manager a .02 runs per PA margin for error, Bonds is now +.13 runs per PA, or .265 chance of winning with Bonds. Mayne’s -.02 runs per PA brings us to .263 win probability if we walk Bonds.
Is this reasonable? Some might think so. After all, how sure are we that Bonds was really +.11 and not +.13 in that situation (a wOBA of .436 compared to .453), or that Mayne was really league average and not -.02 (a wOBA of .340 compared to .323). The stakes were huge, an LI of almost 11, meaning that the situation was magnified eleven-fold. How would Maybe react to such a situation? Olson? We can’t know really. We are talking about trying to extrapolate a player’s known performance into such an unlikely situation. Surely a player’s emotions would come into play, to be brought into a situation that he has never faced before (intentionally walking a batter to force a run to face him). Maybe Showalter thought Bonds was a bit better than we think, and that Mayne would be affected a little bit, or that Olson breathed a (more than nornal) heavy sigh of relief that he didn’t have to face Bonds.
The last line of my chart says “Go With Gut”, and I think that’s a reasonable assessment. In the end, this was a dramatic moment in baseball history, a decision that baseball fans, whether siding for the Giants or Diamondbacks, could reasonably root for or against. This is what baseball is all about.