I have a recurring dream that certainly is a harbinger for my imminent demise. I am in the middle of Main Street in Cooperstown, New York, and on one side of the street are bat wielding stat heads. On the other side of the street and inching nearer are those who treat baseball narratives as gospels, and they are waving medieval maces. The baseball gods expect me to keep the peace, but I am looking for a road to travel by night because there is not going to be a dawn anymore in these parts. I do not even awake with a start anymore when the clubbing starts because secretly I want to see both sides impose unrecoverable harm on the other.
Relievers are being elected to the Baseball Hall of Fame, and those who worship at the Holy Altar of Baseball Statistics are none too pleased. The crux of their displeasure is that relievers do not pitch enough innings to merit induction into baseball’s hallowed grounds. Perhaps they are correct, but the narrative of baseball does not always match the numbers. Before the two sides begin a bloodletting though; let’s take a look at the top relievers Wins Probability Added (WPA).
WPA is a narrative stat – it tells the story of the game. It has very little predictive value, so many people, especially rotogeeks, discard it. We don’t need to re-invent the wheel here, or embark on a long primer. WPA attempts to measure a player’s contribution to a win by figuring the factor by which each specific play made by that player has altered the outcome of a game. From Fangraphs glossary:
“Win Probability Added (WPA) captures the change in Win Expectancy from one plate appearance to the next and credits or debits the player based on how much their action increased their team’s odds of winning. Most sabermetric statistics are context neutral — they do not consider the situation of a particular event or how some plays are more crucial to a win than others…. we know intuitively that a home run in the third inning of a blowout is less important to that win than a home run in the bottom of the ninth inning of a close game. WPA captures this difference.”
Relievers, especially closers, often enter the game under higher leverage situations. By taking a look at Career WPA, we can get a pretty good glimpse of how these pitchers did compared to starters in terms game context.
Top Ten Relievers WPA (Baseball Reference’s all time ranking with all pitchers)
Rivera 56.93 (5th)
Hoffman 34.15 (22nd)
Gossage 32.51 (29th)
Wilhelm 30.84 (32nd)
Nathan 30.60 (34th)
Wagner 29.07 (37th)
Papelbon 28.31 (41st)
F Rodriguez 24.43 (56th)
Percival 23.60 (62nd)
Kimbrel 23.37 (66th)
Others of note:
McGraw 21.51 (76th)
Sutter 18.25 (102nd)
Fingers 16.19 (124th)
Eckersley is at 30.85 (31st), but that has a great deal of starter innings.
We see Mariano Rivera atop of the reliever list, and fifth all time in WPA. The only guys in front of him are named Clemens, Grove, Maddux, and Spahn. Note that these are only regular season stats, and Rivera leads everyone in post season WPA.
If we drop down to 22nd on the overall we see recently inducted Trevor Hoffman just ahead of some guys named Ryan, Marichal and Koufax. The only guys in front of Hoffman who aren’t in the HOF are Rivera, Mussina, Halladay, and Schilling, all who have good chances of getting in. Drop a little further down to HOFers Gossage, Wilhelm, and Eckersley and we see other HOFers like Sutton, Blyleven, and Lyon missed with other non-HOFers. If we go all the way down to Sutton and Fingers, we are not going to find too many HOFers.
I am not advocating that WPA is some slick that offers immediate HOF credibility. First of all it is just one data point, and no HOF career can be defined by one data point. Secondly, WPA does not tell us everything about a pitcher’s performance – it offers one slice of a larger pie. How large of a slice is for greater minds than mind to determine, but we cannot say that Trevor Hoffman’s career was almost equal to Nolan Ryan’s because of their WPA.. It does offer us some context though. Relievers have a different job than starters, and WPA lets us look at both jobs in terms of context though, and context is the building block to any HOF narrative.