Dissecting The Bullpen, Pt I

added 6/30/2013 by Scott Barzilla

If there is anything that is normal for sports fans it is a lack of perspective. Whether you are talking about your team's quarterback, the starting point guard for the basketball team, or a relief pitcher, your team either has the best or the worst according to fans of that team. Think about it. How often do you hear fans say their guy is just average? So, depending on whether you are a glass half full guy or glass half empty guy, you will see any particular player as good or bad.

For most fans, it's never as simple as all negative or all positive. Every fan has their personal favorites and their whipping boys. For most Astros fans, the whipping boy in the bullpen is Hector Ambriz. The embattled pitcher came to the Astros the same way that most of them came: he was a castaway from another organization. Jose Veras is the only pitcher to be signed as a free agent (of some renown). So, it was a surprise when Ambriz was labeled the 8th inning guy at the beginning of the season and he has been dogged ever since.

In essence, you might say that Hector Ambriz is a perfect microcosm of the Astros situation as a team. He's probably good enough to make most major league bullpens, but he likely would be a middle reliever or a long reliever for most of them. Yet, no one would be anything without an opportunity to do it. So, the question is what is Ambriz doing with the opportunity?

This is where a lack of perspective comes into play. Relievers in particular are subject to an unfair standard. Old-timers will tell you that relievers should be able to retire three guys fairly easily without incident. Yet, they have more opportunities to blow up than their starter counterparts. They have to be on their game at least 60 times a season where starters typically go 30.

To judge any particular reliever in the role they are in, you must first judge where they are in comparison with other relievers in that same role. Is Hector Ambriz above or below the league average as compared to other setup guys?

What we did is take the top non-closer from each team in regards to his average leverage index (according to Fangraphs). From there, we took the percentage of games where the pitcher had an opportunity to earn a shutdown (a Fangraphs statistic). That will tell us how much that manager trusts that reliever. Finally, you get the percentage of successful shutdowns. We will first show the top statistic in a particular category, the median statistic, and then the bottom statistic. We can then get an idea of where Ambriz ranks in comparison with his contemporaries.

. . . . . . . . . . . . . . . .G. . . . . . .PCTHL. . . . . . .PCTSD
Top Reliever. . . . . . .40. . . . . . . 784. . . . . . . . ..926
Median Reliever. . . ..34. . . . . . ..541. . . . . . . . ..694
Bottom Reliever. . . ..23. . . . . . ..407. . . . . . . . …438
Hector Ambriz. . . . . 37. . . . . . ..568. . . . . . . . ..571

So, believe it or not, Ambriz is not the worst setup man in baseball. If we consider the percentage of shutdowns as the key statistic, we see that there are actually three relievers that are worse than Ambriz. So, based on the study here, we have confirmed our suspicions that the Astros aren't getting the kind of performance they need from Ambriz. A sarcastic reader would ask why we had to go through this exercise to figure out something we already knew. The answer is that occasionally we find ourselves assuming something that isn't true.

Now that we know where Ambriz ranks, it would be fair to ask why Bo Porter is relying on him so heavily in comparison with the rest of the league? His percentage of high leveraged outings is higher than the median setup man in baseball. Most people would think this wasn't true based on the Astros record, but Porter has seemingly leaned on him in tight ballgames. The question for the next edition will be whether there are any options in the bullpen that would be better for the 8th inning. For now, we can point at this position as one reason why the Astros are struggling the way they are.

Note: The numbers above came from Fangraphs as of June 29th.