This article is part of a series taking a look into individual Diamondbacks player projections as we head into 2024 spring training. The projections presented are a composite of the rate (percentage) stats from Steamer and ZiPS as published on FanGraphs. The playing time projection is our own and is based on the current roster as of the time of this writing. Further roster changes will impact the playing time and thus the WAR projection, but not the rate or percentage statistics presented.
Andrew Saalfrank began the 2023 season with the D-backs' Double-A affiliate in Amarillo, but finished as one of their top left-handed arms in the major league bullpen. With free agent signing Andrew Chafin failing to stabilize the back end of the bullpen, along with Joe Mantiply's injuries and Kyle Nelson's home run problem, the team turned to Saalfrank in September.
He ended up being exactly what they needed, not allowing an earned run in 10 regular season appearances. He gravitated towards the back end of the bullpen in the postseason and got some key outs in the team's run to the World Series. The combination of whiffs and ground balls made him the ideal candidate to get big innings out of the bullpen, although his overall command needs work for him to stick. Once a surprise a year ago, now he's expected to be a big part of the bullpen in 2024.
The Projection
Saalfrank is projected to get in about 40 games, averaging roughly an inning per appearance. That's roughly in the same number of appearances and innings as both Mantiply and Nelson, so he's projected to be one of their top left-handed relief options.
The run prevention numbers won't be as lucky in his first go-around, with the projections giving him a 3.87 ERA and a 4.02 FIP. That would make him the most effective left-handed option in the bullpen, barely edging out Mantiply. Those numbers are based off strikeout and walk rates that are close to the major league average rates for relief pitchers, but slightly worse. The potential of an extreme ground ball pitcher also yields a positive effect on home runs per nine innings, sitting at 0.87.
Why Saalfrank Might Beat This Projection
If healthy, it's not unreasonable to believe he can blow this projection out of the water. If he stays on the roster all season, he'll accumulate at least 60 appearances and 60 innings in the 2024 season. While he'll have to earn a roster spot in the bullpen, his short but impressive 2023 track record has the potential to translate in future seasons.
Saalfrank excels at getting hitters to chase pitches that look like strikes but aren't when they get to the plate. That leads to whiffs and weak ground balls, with a ground ball rate north of 70% in a short sample. He'll need to stay ahead of hitters to continue the trend of getting chases, so the ability to throw strikes early in the count is key.
Why Saalfrank Might Not Beat This Projection
I think the second left-handed reliever spot is Saalfrank's to lose, but it's still possible he gets beat out by Kyle Nelson. For that to happen, he's either hurt or has completely lost the strike zone. The other possibility is the dreaded "sophomore slump." For young relievers, it's not that uncommon to run into some adversity and needing to adapt to how major league hitters adjust to him. Sometimes that includes stints in the minor leagues, other times they're allowed to work through them at the MLB level.
Seeing a pitcher multiple times in a series or season has a cumulative effect and starts favoring the hitters. That was the case in Game 4 of the National League Championship Series, when the Phillies saw him for a third time and laid off pitches they swung at earlier in the series.
Summary
Exceeding 40 appearances won't be too difficult to exceed unless he struggles at the major league level, and Reno to some extent. It's still possible he doesn't match the run prevention numbers, however, given that he has the most run prevention tools at his disposal of all the left-handed relief options in the organization, I would not be surprised if he ends up being their top option from that side of the mound for the 2024 season.
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