The Lefty Ketel Marte Is Performing Better Than Ever

I’ve long been a staunch supporter of Ketel Marte. Switch-hitters with short levers are my personal favorite archetype. When you can produce 90th-percentile max exit velocity from both sides of the plate with only mid-teens strikeout rates, you’ll have my attention each and every night. It’s not always the case that switch-hitters have two contrasting swings, but it is for Marte. He is a natural right-handed hitter, which has played out clearly in his performance over the years, but every now and then, everything clicks on both sides of the plate. In fact, since his breakout 2019 season, he has been an above-average hitter from the left side every other year. But this season, he has taken off unlike ever before.

Throughout Marte’s career, there has been a stark difference in his power from the right side versus his left side. Despite being powerful in terms of exit velocity from both sides, he has always been better at creating pull side lift with his natural right-handed swing. That has resulted in a career ISO of .215 as a righty and .155 as a lefty. But like I said, things are clicking for him as a righty this year.

Before diving into the deep details, let’s look at his splits each year since the 2019 breakout:

There is still fluctuation, but in general, Marte is consistently well above average from the right-handed side. Last year was his worst mark since his breakout, and he was still a 125 wRC+ hitter. But with the more advantageous side of the platoon being the left side, his overall production is highly dependent on how he performs when facing right-handed pitching. So for the rest of this piece, I want to shift my focus to that side. This is the best Marte has been as a lefty since 2019, and that warrants an investigation on what exactly he has done to get here.

First, let’s look at how Marte’s wOBA/xwOBA has improved as a left-handed hitter in specific situations:

In addition to increasing the damage done when he is ahead in the count, Marte has drastically improved his performance against breaking balls after being a downright liability against them in 2022. Some of that has to do with swinging at fewer breaking balls in general, but a lot of it is mechanically related. I’ll get to that later, but for now, just know that Marte hit .186 with a .303 Slg% against breakers in ’22; this year, those numbers are .250 and .520, respectively.

The final piece of this table focuses on batted balls within the sweet spot. Statcast defines that as any batted ball with a launch angle between 8–32 degrees. (The upper end of that range can move depending on how powerful a hitter is, but for the sake of this exercise, we will just stick with Statcast’s definition.) Since these batted balls are all hit within the ideal launch angle, the expectation is for performance to be high regardless of season (or even player). But you’ll notice that for Marte, that number has seen a significant increase from the previous three seasons. Remember how I said that Marte has always been better at creating pull side lift as a righty? This year, he has been phenomenal at it from both sides.

A hitter doesn’t only want to hit batted balls in the sweet spot; they want to hit batted balls hard in the sweet spot. I know that’s a simple statement, but it’s helpful in understanding why Marte has regained his 2019 juice. We’re dealing with relatively small samples here, but the results are highly indicative of performance. After all, for most hitters, the best chance to do damage is on pull side batted balls in the air. This season, Marte has 19 pull side batted balls within the sweet spot range; last season, he had 33. The exit velocity range of these batted balls, though, has compressed in 2023: 79% (14/19) of his batted balls in the sweet spot range this season were hard-hit (i.e., 95 mph or more); last year, that number was only 48% (16/33). To go to the next mathematical step: this year, the standard deviation of exit velocity of these batted balls is 10.3; last year, it was 12.1. This is a complicated way of saying that when Marte hits the ball hard in the air to the pull side as a left-handed hitter, he is hitting a rocket almost every time.

With that knowledge, let’s now look at his swing mechanics to tie this all together. The first three swings are from 2022, and the following three are from this year:

2022

2023

Pay close attention to Marte’s posture and backside before and after his leg lift landing. Something that many hitting coaches preach is having a controlled landing. Depending on the hitter, the force you put into landing will vary, but no matter what, the hitter should have control of that force. Not many people can consistently land heavy into their front side with success. In 2022, Marte would hit his landing, but his center of gravity would slide forward, causing him to lose his balance and, as a result, his ideal swing path. You can see this if you pay attention to the position of his backside and how it relates to his posture/front knee bend. This year, that hasn’t been an issue at all. Even when he has a heavier landing, like you can see in his swing against Anthony DeSclafani, he’s keeping his center of gravity behind his front leg and maintaining his posture until he lets it loose. His swing against Jon Gray is another good example of his ability to maintain an ideal position on a higher pitch. By doing this, he keeps his barrel on a plane where he can square up a hanger and drive it far over the right field wall. This is what strong deceleration can do for a hitter.

My guess is that this slight inefficiency has been cleaned up thanks in part to Marte avoiding hamstring issues. Last year, he strained a hamstring in an injury that lingered for at least three months; decelerating without fully healthy hamstrings is extremely difficult and can absolutely impact swing mechanics. Deceleration is also directly tied to hitting breaking balls, since the body needs to adjust to a different speed. That could be a reason why he has seen such a big improvement against that pitch group this season. Luckily for him, the hamstring issue seems to be a thing of the past, and he has been able to get his lefty swing in the best spot of his career.

It’s been a pleasure to see Marte back in his peak form. After on-and-off performances in the previous four years, it wasn’t clear what to expect from him going forward. The combination of loss of speed and decrease in performance was worrisome, but he has proven he can still be a top tier second baseman, especially in the hitting department. If he can continue his raking ways along with his many talented teammates, his first-place Diamondbacks will be in a great position to maintain their position in the standings all season.