Roberto Osuna: By far the most controversial acquisition by the Astros in recent memory, Osuna is the likely closer for the club in 2019. Despite a 12.27 ERA in the ALCS against the Red Sox, the former Blue Jay did post a 1.99 ERA across 12 relief appearances following his trade to Houston. The Astros are counting on Osuna to provide some stability in the backend of the bullpen again in 2019. That said, he ought to be on an extremely short leash for the upcoming season, especially in light of how serious his off-the-field situation was this past year.
Cionel Perez/Framber Valdez (again): The Astros are likely staying within the organization to find a left-handed reliever, which means Perez and Valdez are candidates for the job. If Valdez earns a role in the rotation, then Perez likely has the inside track to the job. Heck, he might anyway even if Valdez doesn’t break camp in the rotation. Of course, Valdez had a successful debut in the majors last season with a 2.19 ERA in 37 innings, some of which came as a reliever.
Chris Devenski/Will Harris/Brad Peacock/Hector Rondon: Although the Astros had one of the better bullpens by the metrics, there was a bit of volatility within the unit. For example, Devenski, Harris, Peacock, and Rondon were either the ALDS and ALCS roster, or all together. All four had high and low moments during the regular season, but it is clear that the Astros’ confidence in them waned at times. All four could possibly return to key roles in the bullpen in 2019, but we’ll see how Spring Training pans out first.