I consider win probability added (WPA) to be the ultimate “story” stat—it tells you exactly who the heroes and goats were. Sabermetricians have pretty well disproved the myth of consistently clutch players; players are generally who they are regardless of the situation. Due to random variation, some players are going to have extremely clutch or un-clutch seeming games and seasons when they do or do not come through in crucial situations. I think of RBI in much the same why I think about WPA. RBI numbers do not tell us a great deal about a player’s individual talent, but they do tell the story of who knocked in the runs when guys were getting on base ahead of them. But WPA paints a more exact picture of how players performed in all of the contexts presented to them.
Here is a full explanation of WPA. Here is my short version: the sum of the change in a team’s chance of winning before and after each plate appearance. (It can be applied to pitchers as well, but for this post, I will only focus on hitters.) Keep in mind that for hitters it is a purely offensive number; defense does not enter into it.
I have parted ways with two American dollars for the pleasure of diving into the best and worst WPA performances in Royals history via the Baseball-Reference.com Play Index Tool. The most gob smacking find is Neifi Perez’s horrific 2002 WPA. Royals fans know the shortstop received in exchange for Jermaine Dye was an abomination, but they may not know his -6.8 WPA that year is the worst in at least the last 60 MLB seasons, and possibly of all time. (WPA is not available prior to 1950 on Baseball-Reference.) No other season in the last 60 even comes close. Perez’s plate appearances in 2002 decreased the Royals chances of winning by 682%, or close to seven games worth.
Worst MLB WPA single seasons, 1950-2010:
Neifi actually had a pretty good opening day in 2002. He went 3-for-5, moved some runners over with a single, knocked in a run with a triple, and scored two runs himself. His .047 WPA was good for second best on the Royals lineup that day. However, a sign of things to come occurred on the last play of the game: Neifi was up in the bottom of the ninth, Royals down 6-8, two on and two out. The Royals clung to a 10% win expectancy, but Neifi popped out and the game was over. On April 24th, he was the Royals WPA hero with a 3-for-4, three RBI game. But the good days were a rare exception in this season from hell.
Our Neifi came to the plate 585 times that season. Crucial moments of games seemed to find him. Alas, he was rarely up to the task. After only five percent of his plate appearances did he leave his team in a better position to win. Five percent! I do not even understand how that is possible when he got on base 26% of the time, but there it is. He had a few especially disastrous games, but he achieved the historic low more by being consistently bad day in and day out. With runners in scoring position, his already dreadful offensive skills tumbled even lower to the tune of .221/.246/.270. The Worst Season A Royals Player Ever Had may have hit its nadir when Perez refused to enter a game:
Perez…created a major clubhouse incident by refusing to enter a Sept. 9 game against the Chicago White Sox as a defensive replacement for rookie Angel Berroa. Perez later said his refusal was a joke that was misinterpreted, but his action caused a rift with several teammates. Many privately called for his immediate dismissal from the club.–Bob Dutton, November 19, 2002 Kansas City Star
Neifi makes Angel Berroa look like a golden god. Here are the Royals worst WPA single seasons:
Jason Kendall sighting! Kind of ironic that Jermaine Dye makes the list.
Here is a happier list, the Royals best WPA single seasons:
At the other end of the spectrum is another team hall-of-famer. Frank White reached a positive WPA in just two of his 18 seasons. Good thing he had that golden glove.
Royals worst career totals:
Bringing things to the present, here is how 2011 Royals hitters are shaping up this season:
Escobar is bringing up the rear in all of the majors, and is on pace to enter some seriously unpleasant territory. At his current pace, if he equaled Perez’s 585 plate appearances, he would end up with -8.7 WPA. Ruh-roh.