Sox Watch

Wednesday, July 19, 2006

Red Sox WPA through 7/19/06

Less than 24 hours after Jon Lester turned in the best starting pitching performance of the season, Josh Beckett exceeded it - at least as measured by WPA. Beckett earned a total of +0.607 WPA for this afternoon's game, scattering four hits in eight innings and combining with Papelbon for the second consecutive 1-0 shutout.

Why did Beckett earn more WPA than Lester did yesterday (Lester had +0.592 yesterday)? They both pitched eight shutout innings, and Beckett allowed four hits while Lester allowed just one. From a WPA perspective, though, the hits are not too important - as long as they don't turn into runs. For a pitcher who starts and finishes an inning in which no runs score, the WPA for the inning is determined solely by the difference between the Win Probability at the beginning and end of the inning. What happens in between does not matter - the pitcher loses WPA for allowing hits, but gains it back for the subsequent outs, which are worth more WPA with men on base.

So why aren't the totals for the two games the same? Lester had a bit more support from his defense, which took a little bit of his WPA away from him. I credit defensive players who make great plays with some of the WPA that would otherwise accrue to the pitcher. In Lester's game, I gave 25% of the WPA credit for the pickoff of Grudzielanek to Youkilis, who executed a tough throw to second, and I gave 25% of the credit for the out on Gathright's bunt attempt in the eighth to Lowell, who fielded it cleanly and fired a shot to first. Beckett got a bit of help too (Manny's catch of Phillips' liner in the fifth), but it was not worth as much as the help Lester got. Beckett therefore finishes with a slightly higher total, and takes his place as the best starting pitcher WPA performance of the year.

Individual Player WPA Contributions
Wednesday, 7/19/06
Royals 0, Red Sox 1

Full-Season Player WPA Contributions
Through Wednesday, 7/19/06

Full-Season Category WPA Contributions
Through Wednesday, 7/19/06


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