Last time, we took a look at starting pitcher projections for ERA. We will do the same here for relief pitchers. Obviously, there is a ton to get into here and before we dive in we need to talk about some issues that come up with all pitchers. Certainly, hitting and pitching is partially reliant on luck. Over the last decade, there have been exciting advancements in data primarily from a company called Statcast. They essentially can pinpoint exit velocities on batted balls and therefore can better predict trends in performance.
Chuck Palahniuk (the author of “Fight Club”) wrote one of my favorite lines in literature: “on a long enough timeline, the survival rate drops to zero.” Generally speaking the more data we receive the more reliable that data is going to be. We can predict outcomes and the underlying data (like Statcast) will match the manifesting data. In other words, pitchers that miss bats and induce weak contact will perform better than pitchers that don’t.
However, when you condense a 200 inning season into a 50 inning season, there are fewer opportunities for the data to normalize itself. This is why we often see wide variations from one season to the next for relief pitchers. They themselves are likely not radically different. They are getting different results because when sample sizes are smaller, there is more variance with luck.
This has two immediate implications for us today. First, the idea of giving a relief pitcher a multiyear contract is a risky proposition because of this variance. That’s why we don’t see them very often and it is much rarer for teams to get consistent bang for their buck. Secondly, the ERA predictions will seem higher for some players than what is likely to happen. When we go with batted ball statistics we tend to see a narrowing in projections across different pitchers because we cannot predict good or bad luck. For starting pitchers, that usually is not as big an issue. For relievers we will see wider variation in these numbers when the season ends.
The Numbers
| Steamer | ATC | The Bat | OOPSY | B-Ref | Aggregate | |
| Josh Hader | 3.29 | 3.25 | 3.39 | 3.00 | 3.41 | 3.27 |
| Bryan Abreu | 3.24 | 3.20 | 3.65 | 3.07 | 3.18 | 3.27 |
| Bryan King | 3.72 | 3.63 | 3.65 | 3.70 | 3.48 | 3.64 |
| Bennett Sousa | 3.60 | 3.66 | 3.96 | 3.43 | 3.78 | 3.69 |
| Steven Okert | 3.99 | 4.01 | 4.07 | 3.61 | 4.02 | 3.94 |
| AJ Blubaugh | 4.35 | 4.29 | 4.02 | 4.36 | 3.35 | 4.07 |
| Miguel Ullola | 4.18 | 4.15 | 3.72 | 4.45 | ——- | 4.13 |
| Jayden Murray | 4.61 | 4.39 | 4.22 | 4.22 | 3.86 | 4.26 |
| Enyel de Los Santos | 4.27 | 4.42 | 4.82 | 4.26 | 4.36 | 4.43 |
| J.P. France | 4.38 | 4.45 | 4.82 | 4.91 | 4.34 | 4.58 |
| Roddery Munoz | 4.48 | 4.76 | 4.94 | 4.39 | 5.12 | 4.74 |
Just like with the starters, we have more relievers than spots. MLB rules dictate that you can only have 13 pitchers on your ML roster. If the Astros go with a six man rotation then that means only spots for seven relievers. Naturally, at least one of those starters would probably double as a long reliever. However, there are eleven names here and all of them have unique situations as it pertains to options and status. For instance, Munoz looks like the worst candidate, but he was a Rule V draft choice, so he would need to remain on the roster or be sent back.
You will also notice that four of the top five relievers are lefties (in bold and italics). That creates some interesting roster construction issues as the Astros will need to prioritize right handed middle relief if they are to make any changes to the staff. Most organizations have only two lefties in their pen, so the Astros appear to be dealing from a position of strength. It is certainly possible for one or more of them to be dealt in a theoretical deal to add to other parts of the roster.
Roster Flexibility
As we noted in the last piece, Nate Pearson was projected as a reliever, but the Astros have labeled him as a candidate for the rotation. Similarly, Miguel Ullola and AJ Blubaugh were starters in the minors, so they could easily serve in that capacity. We also should note that JP France was a prominent start on the 2023 club before arm injuries limited him. He could also return to the rotation in Sugar Land to provide more depth in case of injuries.
As much as we would like to see the very best 26 guys on the final roster, teams often have to make difficult decisions at the end of the rotation and bullpen. As previously mentioned, Munoz has to make the final roster or be sent back. If they feel he is reasonably close in quality to a player with options then those players with options will likely be optioned back to Sugar Land. Teams use err on the side of keeping as many of their guys as they possibly can.
Fans and analysts also often forget the fourth dimension: time. Just because someone starts in AAA doesn’t mean they will end up there. Sometimes players need a little seasoning before coming up or they need to wait for a logjam to clear itself. We saw that with the rotation last season as there were even a couple of rotation arms I left off of the final list. Odds are pretty good that every name above will see some time at the big league level.
Future Considerations
I mentioned the reluctance to sign players to multi-year contracts. That will be put to the test following the season when Bryan Abreu becomes a free agent. Abreu is the only relief pitcher in baseball with 100 or more strikeouts in each of the last three seasons. He has averaged nearly 100 a season for the last four years. Add in a fifth season this year and there will be a ton of pressure to sign him to a Rafael Montero like deal.
However, we should note what happened with Montero. Obviously, Abreu has a longer track record of success than Montero did, but the question remains. How long will he be able to hold up this level of performance? Some team will likely offer him closer money and it is hard to imagine paying two players closer money. So, a large part of the season will be trying to find that guy that can eventually become the 8th inning guy when Abreu walks in free agency.
I hesitate to suggest it because the names above are generally unproven, but the Astros might consider moving him before the deadline. If they do not foresee re-signing him then it makes sense to consider getting something long-term to help your team. However, leaving your team without an effective 8th inning reliever is not conducive to contending, so the Astros will need to either be out of the race or have someone that can immediately take his place.
