So why does Yusei Kikuchi play second fiddle to Dennis Sarfate in win shares? The essential answer is context.
First of all, it is very hard for relievers to rank so high unless they are extremely dominant and pitch a fair number of innings and get lots of saves – indicating many high leverage innings and that moves Sarfate into the conversation.
Still, the win shares system recogizes that Kikuchi was better at one level – the estimated contribution his raw numbers made to his club’s success. So why does Sarfate end up on top despite that.
The answer is wins. Not being credited with wins as the pitcher of record, but team wins.
On one level, this is a normal part of the system: Teams that win more games have more credit for wins to be shared by their players. But in the Pacific League in 2017, the Hawks won four games more than their run production and prevention would predict, and the Lions five games fewer.
Because the system is anchored on wins, you can’t get around the fact that in the big picture, the Hawks’ players’ numbers were therefore more valuable than the Lions’ players – who needed to score and prevent more runs to produce the same number of wins.
The system rewards individual performance on claim points. Pitchers get points for preventing runs in your innings beyond that which your fielders are credited with saving the team per inning.
You get points for striking out more batters and walking fewer, and for giving up fewer home runs. Because Kikuchi pitched nearly three times as many innings, he was able to save many more runs, but Sarfate was extremely effective and had a high leverage bonus because of his 54 saves. Still, Kikuchi gets 87.8 claim points – more than Sarfate’s 75.5.
Kikuchi’s claims give him 21 percent share of the Lions’ pitchers’ win shares. That is larger than Sarfate’s 17 percent of the Hawks total. But because the Hawks’ players’ numbers were more valuable, a Hawks pitcher saving 20 runs in 100 innings (adjusted for context and team defense) created more wins than a Lions pitcher who did exactly the same.
The Hawks’ individual performances were not all that much better, but in terms of wins, they were noticeably more valuable. Because the Hawks pitching staff produced many more wins, Sarfate’s contribution to the Hawks was a smidgeon more valuable than Kikuchi’s contribution to the Lions.
This connundrum pops up when the star of one team that wins more games than its runs scored and allowed suggest is compared to the star of a team that wins fewer games than it ought to. The Hawks won four games more than expected, the Lions five fewer. But you have to give the credit for that to the players, meaning, the Hawks’ players’ stats need to carry slightly more weight than the Lions.
That’s the rationale.
Is it accurate? It has its failings here and there, and it is not hard to believe that somehow Kikuchi must earn more credit, but in the end, everything depends on wins. At least this system doesn’t give players credit for winning games that their team didn’t – as WAR would.
If the Lions’ wins had more accurately reflected their runs and runs allowed, then the system would have seen Shogo Akiyama as the PL’s most valuable player – instead of Yuki Yanagita.
It also explains the presence of so many BayStars players and the absence of Tigers. The BayStars were hyper efficient, while the Tigers were not.