Why the Yankees don’t have more lefties in the bullpen

In a typical bullpen construction, you have a group of righties and a handful of lefties. Ideally, each of these pitchers provides different offerings in terms of repertoire to diversify what hitters see. This is a strategy that the Yankees have done a great job at employing. However, heading into 2023, the team’s bullpen is still stacked with talent, but only has one lefty in Wandy Peralta. The 31-year-old southpaw will certainly be an important contributor, but if he goes on the shelf for any period of time, the team will be stuck without any lefties unless they have a surprise up their sleeves. The question I want to answer is how big of a problem is that, if at all?

For the Houston Astros, it wasn’t at all a problem in the playoffs. Kyle Kishimoto of FanGraphs detailed why the Astros didn’t skip a beat despite not rostering a lefty in the first few rounds of the playoffs. Basically, the idea is that if you’re a righty and you have a go-to pitch that is tough on the swing path of lefties, then why is it necessary to roster a group of lefties if they aren’t as effective as your righty options?

This idea is entirely applicable to what the Yankees plan on doing in 2023 (given their trade of Lucas Luetge), and I’m completely on board with it. Below is a table detailing some statistics that the Yankees’ righties had against lefties in 2022.

Other than Lou Trivino, each of these righties is between viable to elite against left-handed batters. I’d argue that Jonathan Loáisiga’s numbers will improve next year relative to ’22 because of his bounceback in the second half. Even so, the team has Tommy Kahnle, Ron Marinaccio, and Michael King as elite options out of the pen to get lefties out. Those three on top of Peralta give the Yankees ample options to handle whichever group of lefties they might face during the year. To get an idea of why these pitchers are so tough on lefties, you have to understand their pitch repertoires.

Intuitively, if you’re a right-handed pitcher and you draw up the ideal repertoire to get lefties out, you will need to include a changeup that has a movement profile that dips under the lefties’ bat paths or away towards the end of their barrels. It’s understood that Kahnle and Marinaccio have elite changeups. In fact, there is an argument to be made that each of them has a top five right-handed changeups in the entire sport. In 2022, players hit .142 against Marinaccio’s changeup. For Kahnle, opposing batters hit .094 against his changeup and .130 in 2019 — his last full season. These two are a nightmare for lefties because of their fastball-changeup combo. If you forgot what they look like, check them out.

King also has a decent changeup of his own. He only threw 64 against lefties this year due to his injury, but they only hit them at .100 clip with not a single extra-base hit. He hardly uses it against righties, because he typically doesn’t have to, but against lefties, it’s a secondary weapon.

Pairing that with a four-seamer with decent shape and a wicked whirly, he is a tough matchup for a lefty because he is simply hard to square up. Here are examples of both those pitches getting outs in various ways.

Like his two bullpenmates, King has weapons to use against lefties. He might not be used as frequently against them, but this skill allows him to be the multi-inning reliever that we saw in the beginning of the season.

With King, Kahnle, and Marinaccio ready to support Wandy at any time, the Yankees are in a better position than most teams to face lefties. When you consider that, plus the team having two very good options in Carlos Rodón and Nestor Cortes, facing lefty hitters might end up being a strength for the team.