A New Strategy for Building the Back of the Bullpen
The Astros have used MLB veterans to fill out their bullpen in recent years. This year, they seem likely to cycle through several low-cost options to find effective options. I assess this shift
The big news of the Astros offseason was signing free agent Josh Hader to join incumbents Ryan Pressly and Bryan Abreu in the back of the bullpen. The Astros now have three of the top 25 relievers in projected fWAR for the 2024 season.
The Astros are secure in the back of their bullpen, but that leaves open the question of what will happen with the rest of the bullpen. The Depth Charts projection at Fangraphs says the Astros need to absorb 321 innings from “the rest of the guys” in their bullpen.
How will they do this? Differently than they have in the past. In recent seasons, the Astros have had a relatively set bullpen composed primarily of major league veterans.
The 2024 team will instead have a large number of potential options for the final four bullpen spots and the team will sort through them to find the best option. Over the last six months, the front office has acquired replacement level talent from other major league clubs and put them in competition with a large set of young players and prospects.
It’s a clear shift in how this team is building its bullpen and I examine it below.
Lots of New and Cheap Additions
Since September, the Astros have added three bullpen arms to the 40-man roster:
Bennet Sousa, a lefthander who was picked up off of waivers on September 3.
Oliver Ortega, who was claimed off of waivers in late October after being DFA’ed by the Twins.
Dylan Coleman, acquired in a trade in early December for a minor leaguer.
In addition to acquiring these players who are on the 40-man roster, the Astros signed two pitchers with major league experience to minor league contracts with an invitation to major league Spring Training: Wander Suero and Tayler Scott. The team also acquired Joel Kuhnel last June, and he is on the Astros Spring Training roster.
Will any of these six pitchers help in the bullpen in 2024? The answer for each one individually is “probably not.” Five of these six were designated for assignment by their previous teams. The other one—Dylan Coleman—was shipped away from the Royals after a disastrous 2023 season.
But collectively they probably will help. One of the six might break through, in part because if you increase the number of low probability actions you take, the chances that one of them works out is higher.
Reliever performance is volatile. Some of that is do its smalls sample size—60 innings a year. Some is due to the small margin of error that separates a guy on the back end of a major league roster from a minor leaguer. Small tweaks to pitching mechanics, preparation routines, or pitch mix can produce bigger changes in outcomes.
Coleman is a good example of this. In 2022, Coleman had an excellent year out of the Royals bullpen, sporting a 2.78 ERA innings. In 2023, he regressed badly, with an 8.84 ERA in only major league 18.1 innings. Not surprisingly, the Royals shipped him back to AAA.
What went wrong for Coleman? One answer is that he pitched in good luck in 2022. Thanks to a below average BABIP and home runs per fly ball rate, he overachieved his 3.78 expected ERA. The other is that his control betrayed him. Coleman walked 12.8% of batters he faced in 2022 and 19.8% of batters in 2023 (Yikes!).
The Astros hope is that adjustments from their player development operation will get Coleman back to being an effective reliever. Since he’s done it before, there is good reason to think that hope is in vain.
Another example is Sousa, who was placed on waivers three different times in 2023. He had a 4.43 ERA in 20.1 AAA innings last season. But the Astros added him their their expanded rosters in September, and he was excellent. He struck out 8 while allowing only 1 hit, no walks, and no runs in 6.1 innings.
A Change in Philosophy?
In the last two seasons, the Astros have had a relatively set bullpen featuring veteran options such as Ryne Stanek and Phil Maton. Neiter Stanek nor Maton turned into high leverage weapons in Houston, but both were reliable. Both have left as free agents, and the Astros must try something new.
Rafael Montero is back in large part because his contract compels it. The Astros will hope that his odd year bad-even year good pattern re-emerges this season after a disastrous 2023. Kendall Graveman likely would have served in the Stanek-Maton role of dependable bullpen veteran, but he will miss the season after shoulder surgery.
As a result, there are four spots in the bullpen where there is an open competition this Spring Training. The six pitchers spotlighted above are each candidates for one of those spots. They are competing against holdovers like Brandon Bielak, Seth Martinez, Parker Mushinski.
In addition, prospects such as Forrest Whitley, Shawn Dubin, and Colton Gordon are candidates to make their major league debuts this season, possibly on Opening Day.
Again, one should not expect that any of these pitchers will push their way past the established high leverage trio like Bryan Abreu did in 2022. But the goal is not to replicate Abreu. It is to get the league average bullpen production we saw from relievers such as Stanek and Maton over the last two seasons.
None of the individual options available for the back of the Astros bullpen are likely to achieve this as veterans such as Stanek and Maton. But collectively, the Astros are likely to unearth a gem, or just to get volatility to work in their favor for one of their many options. Or at least, that’s the hope.
Personally, I am really excited to see whether Sousa can continue his strong finish from 2023. If I'm not mistaken, the Astros indicated he would've made the postseason roster if he had been acquired in time to be postseason eligible. It sounds like they like him a lot and will give him every chance to be successful.
As for the others, I am optimistic that they can find success particularly in platoon opportunities. For example, Seth Martinez might return to prior form if he can be deployed in (limited to) primarily RHB opportunities. Similarly, Parker Mushinski may find more success if limited to LHB work.
Of course, innings need to be covered and there's the batter minimum to consider. You can't hide behind platoon splits forever over the course of 162 games. But, perhaps the presence of the dominant 7-8-9 of Abreu-Pressly-Hader and more LHP in the bullpen than in prior years, enables more mixing and matching in those middle innings.