WPA/LI (aka Situational Wins) is perfect for hitters, since it values each PA as “1″, which is really what we want to do, to make a fair comparison.

However, what we *really* want is something in-between WPA/LI and WPA for a pitcher. A pitcher doesn’t just come into a PA like a batter, but he creates the environment. And so, each PA must be worth more the more runners are on base. We really need to multiply the WPA/LI by the LI for the base/out state. A bases empty situation has an LI of 0.7, while one with the bases loaded is say 3.0 times. That’s what you really want to do: WPA/LI * boLI.

For a season, a pitcher’s boLI will come in pretty close to 1. Even if it doesn’t, the boLI of all the top pitchers will be close to each other so that they will all be similarly biased.

For a single game however, it might make a difference.

http://www.baseball-reference.com/boxes/DET/DET197308040.shtml

If Tim Linsecum were to begin pitching the 3rd with the score tied at 0, walked the bases loaded, and then gave up a line-drive DP with a forceout at home, and a 395 foot fly ball that stays in the yard in dead center, the effect on WPA is the same as if he struck out the side in 9 pitches. It goes from the probability of winning with the score tied when you’re on the field to that same situation in your next turn at bat. Regardless of what went on that inning, same result on the scoreboard = same WPA.

Of course, it’s not totally meaningless, because if a pitcher is bad (results-wise), he loses WPA and has to get bailed out by the offense. Of course, if he’s good, the offense has to stink it up for him to register a gaudy WPA. Assume a scoreless tie. If a pitcher pitches a 1-2-3 inning, his team has an extra turn at bat, so their chances of winning are at that point slightly higher. If the offense blows it, the two teams return to equal footing, and the pitcher has to regain the lost WPA advantage of the extra inning. Repeat the process 8 times, and you have the maximum WPA any pitcher can have in a 9-inning game regardless of who wins provided the starter does not give up the winning run.

I don’t know where you’d go to search single game WPA’s, but using the first set of criteria, I’ve found a couple of historical >1.0 WPA games. frank tanana threw 13 shutout innings on september 22, 1975, and ended up with a WPA of 1.132, and Tommy John had a game in 1983 where he threw 13 shutout innings and came away with 1.217 WPA. I only checked two of the games on that PI query, and both succeeded, so I’m sure a number of other pitchers have done it, as well.

OTOH, I’d bet this is something we never again see, at least by the first set of criteria. Mark Mulder’s 2005 10IP CGSHO was only .832 WPA, and that is about the limit i see any modern pitcher throwing.

(hope those links worked ok- i hate not having a preview button here)