J.D. Martinez Is Back

As a hitting mechanics nerd, there are a few players on my shortlist of guys who I would love to get in the cage with and talk about their process, development, and mindset in the batter’s box. J.D. Martinez is one of them. He’s established a reputation for himself as a cerebral hitter. It was a key reason for his breakout season in 2014, his rebound in 2021 after a rough shortened season in 2020, and now his resurgence in 2023. Despite an IL stint earlier this month for a back issue, Martinez has destroyed baseballs recently and pushed his wRC+ up to a 146 on the season. In May alone, he posted a 172 wRC+ and .392 ISO.

His power stroke is back after working on recovering it with Dodgers hitting coach Robert Van Scoyoc throughout spring training and the opening month of the season. The Athletic’s Fabian Ardaya spoke to Martinez and Van Scoyoc in early April about Martinez losing efficiency in one of the most important aspects of his swing: his hand row. Martinez pointed to a line of physical compensations in his swing as a result of an ankle injury from the 2018 World Series that he reaggravated down the stretch in 2021. When you’re as in tune with your mechanics and where your barrel is in space as Martinez is, these little aggravations can significantly impact the way you understand how your body is moving. Before jumping into some video showing how Martinez has changed since last year with Boston, let’s take a look at some batted ball and performance data that detail how much better he has been this season:

These data points show that Martinez was already darn good last year in terms of quality of contact despite not being the best version of himself. Only three other players in the league have had bigger jumps in xwOBACON from last season to this one, and none had greater than a .400 mark in 2022. To turn it around and have his highest xwOBACON since 2017 (when he hit 45 home runs in 119 games) is remarkable.

When I wrote about Martinez’s signing during the offseason, I explained how some of his lost damage came from not punishing mistake breaking balls like he had in previous seasons. In Ardaya’s piece, he notes that Martinez wasn’t able to adjust to different sequences because of the loss of efficiency in his upper body mechanics. With Martinez turning that around, his performance against breaking balls has rebounded as well. Below is a table detailing that progression:

Martinez’s .630 mark in the heart of the zone won’t be that high when the season ends, but it is evidence that he has gotten his bat path back to the point where he can cover breaking balls and fastballs with hard contact in the air. He continued to hit fastballs extremely well last year even with the overall downward trend, so a focus on extending his bat path to be more adaptable to breaking balls made sense. When you already have a blueprint for success, it can serve as a reminder for what you need to look for when you’re struggling. Martinez may not exactly be thinking that he needs to be better against breaking balls, but his adjustments have led to it.

In terms of plate discipline, there haven’t been any major changes year-over-year, or even compared to any other year during his prime. Just about everything is in line with his career norms, from chase rate to swing rate. The only notable point is that Martinez seems to be hunting what Statcast calls “meatballs” more frequently. At 93.6%, he is swinging at a career-high rate against these pitches. Given how much damage he has done in the heart of the plate, that tracks well!

Now, let’s get to his mechanics. Since Martinez and Van Scoyoc were focused on the hands, we’ll do the same. Sometimes front facing video is hard to come by, but thankfully Craig Hyatt has been on top of it. The first swing here is from last season, while the second one is from this season:

Martinez HR! pic.twitter.com/UIOXIKoe6q

— Craig Hyatt (@HyattCraig) October 6, 2022

J.D. Martinez – Los Angeles Dodgers pic.twitter.com/ppokOT77Xb

— Craig Hyatt (@HyattCraig) January 1, 2023

The first video comes from October of 2022. Martinez had been much better in this month than in previous ones, so he was tracking closer to his peak self, but there are still notable differences. It’s a shame we don’t have access to more video like this since it’s the best way to illustrate changes in upper body mechanics, but that’s okay. This is enough to show how still Martinez’s head and front side stay as his hands go through their process. This slightly quieter movement looks more effortless. When hitting and pitching coaches talk about efficiency, one easy way to see if an athlete is moving more efficiently is if it looks effortless. Effortless movements are deceiving for athletes this powerful. You might think the hitter (or pitcher) looks like they aren’t trying, but that’s because everything is sequenced perfectly.

In that same interview with Ardaya, Martinez mentions still being able to get by with the mechanics he had his last few seasons in Boston. He was talented enough to routinely beat fastballs and be an above-average hitter, but he needed something else to make him smoother and more adaptable. By focusing on his hand row before making his forward movement, his hips are no longer sliding forward too early in his swing.

Hip sliding is a bat path killer. When your center of mass drifts forward before you create separation with your upper body, your bat path is cut off and you become a more one-dimensional hitter. It decreases the length of stretch you can make in your body as you’re waiting to pull the trigger. The longer you can hold your athletic stretch, the more room you have for releasing a quick snap. Or put another way, the more adaptable to different pitch speeds you are. This change has helped Martinez stay on elite backdoor sinkers, as he did when he hit this 105-mph line drive against Michael King:

Or sliders, as with this 104-mph line drive against Spencer Strider:

Or changeups, like when he stayed on this Josh Fleming offering long enough to smoke it to the pull side:

This is Martinez’s game – scorching offspeed and breaking balls to the left half of the field, and fastballs from the big gaps towards right field. By better aligning his hands with his hips, he is in a better position to make barrel and body adjustments depending on pitch speed and height.

We’re witnessing the best version of Martinez we have seen in years. From a batted ball perspective, he is all the way back. His walk rate might be under 6% for the first time in a long time, but the quality of his contact is more than enough to make up for it. Assuming he can stay healthy for his new club in LA, this one-year deal is shaping up to be one of the best signings of the offseason.