Why Keeping Josh Hader in the Bullpen Makes Perfect Sense


Another offseason, another six months of controversy surrounding the Brewers’ usage of Josh Hader. It has pretty much become tradition at this point, right?

Although Craig Counsell seemingly put the issue to rest in his post-season press conference, I anticipate that Twitter and the Brewers’ Facebook comments thread will be filled with fans vouching for Hader to be inserted into the starting rotation. Hopefully, this article changes their minds and illustrates the vital impact that Hader has as an elite “fireman” out of the bullpen.

What is a “fireman”, you may ask? A fireman is a reliever utilized in high leverage situations regardless of the inning, often pitching multiple innings if needed. I was introduced to the concept in Brian Kenny’s book “Ahead of the Curve”, and it fits Josh Hader’s role perfectly.

The Brewers typically save Hader for situations with the Brewers holding a close lead, and insert Hader to shut down the opposing team’s lineup. This could occur in the 5th inning, or the 9th inning, or the 3rd inning as we saw in the NLCS. The point is, Hader pitches when it matters most, allowing the Brewers to maximize on his utilization. He is a true fireman, getting the Brewers out of the most desperate of situations.

Using Hader in this manner has allowed him to significantly impact the Brewers’ chances of winning in nearly every appearance. Fangraphs tracks a statistic called “Win Probability Added”, which is described as follows:

“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.” (link for further reading, if interested).

One important take away from this definition is that the statistic is not context neutral. With ERA, all runs are created equal. A run given up in the 9th inning of a tie game is counted in the exact same way as a run given up in the 5th inning of a blowout. WPA, however, tracks the change in win probability which resulted from that run being given up, which would be a large decrease in the case of a 9th inning tie and only a marginal one in the case of a 5th inning blowout. This makes success in high leverage situations much more valuable, which better reflects the realities of player performance.

So, how does this relate to Hader? Well, as a relief pitcher, Josh Hader achieved the 13th best WPA of all pitchers in 2018 (for those wondering, Jeremy Jeffress finished 5th).  In fact, Hader finished ahead of elite starters such as Gerrit Cole, Mike Foltynewicz, Patrick Corbin, Zack Greinke, and many, many more. Of the 12 names ahead of Hader, 9 are starting pitchers. To emphasize: only 9 starting pitchers impacted their team’s chances of winning as much as Hader did for the Brewers.

By performing at the level that he does in the situations the Brewers place him, Hader affects the Brewers chances of winning much more as a reliever than he could as a starter. As big of a Hader fan as I am, I do not think that he would perform well enough in a starting role to place him in a WPA position that is better than all but 9 starters in the league. While he certainly would be an effective and valuable starter, he would not provide the same high leverage utility that he does in his current fireman role.

The beauty of Hader as a fireman is that the Brewers get to pick the spots where he can most impact their chances of winning. Should he be a starter, the Brewers could essentially waste his shutdown innings if they take a large early lead, say 6-0 after 2 innings. While Hader would still be providing value in the form of putting zeroes on the board, he would not be changing the Brewers’ probabilistic outcome of a victory as much as if they saved him for a one-run game in the 8th inning the next day.

The Brewers’ usage of Hader is not “traditional”. It is not how the game is “supposed to be played”, at least according to several analysts (looking at you David Ortiz, John Smoltz, and Alex Rodriguez). However, there should be no arguing with its effectiveness, and all of Brewers’ Nation should applaud Craig Counsell’s willingness to adapt cutting edge, analytical strategies like this one that put the team in the best position to succeed.


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