The most volatile unit of any team in the majors is the bullpen. Projection systems struggle to predict accurately the success or lack thereof of a bullpen for any given team in any given year. Dan Szymborski discusses a discrepancy in projections between the two systems: Steamer and ZiPS.
"Where Steamer views the team’s bullpen as middle of the pack, ZiPS much prefers the team’s second-tier relievers, seeing Chris Stratton, Génesis Cabrera, and Andre Pallante as plus contributors, while Steamer thinks of them as closer to replacement level."- Dan Szymborski
The bullpen, headed by Helsley, Gallegos, Pallante (high innings), Hicks, and Zack Thompson was supposed to be relatively strong for the team. Despite having a dearth of left-handed options, ZiPS still believed the bullpen to be a strength for this team, accruing a total of 5.0 WAR over the course of the season.
After those listed players, ZiPS expected players such as Chris Stratton, Genesis Cabrera, Jake Woodford, and Drew VerHagen to provide some relatively effective innings out of the bullpen. The projected strikeout percentage was high in addition to low FIP numbers. The bullpen, with erratic pitchers who have high ceilings, was susceptible to home runs and walks, however.
In reality, the bullpen has struggled. Poor appearances by Jordan Hicks (16.5% BB% and 1.7 WHIP), Genesis Cabrera (13.8 BB%, 2.10 HR/9, and 1.636 WHIP), and Andre Pallante (4.45 FIP and 1.419 WHIP) have hampered the team's ability to use these pitchers in high-leverage situations. Marmol has in turn been forced to use Helsley, Gallegos, and VerHagen in situations that would not normally require their services. Furthermore, Zack Thompson was sent down to AAA to build up as a starter for 2024 and beyond.
While the bullpen is always tough to predict and quantify, the Redbirds' bullpen has had weak spots, making it difficult for other players to thrive in their planned spots.