Written by: Estee Rivera (@esteerivera42)

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Bo Bichette, Vlad Guerrero Jr. and Cavan Biggio. These are the three names that come to mind when we envision the Blue Jays’ accelerated rebuild. They all have the flashy names of former elite big leaguers. Two hall of famers and another with 274 career dingers. Yet, none of these three legacies were the most productive hitter on a 2020 Blue Jays team that returned to the postseason after a 3-year hiatus. That title belongs to Teoscar Hernández.

To put it simply, Hernández absolutely deleted baseballs last year. Not only did he have the biggest positive change in xwOBACON (.439 to .533) in all of Major League Baseball, but he also led his team in home runs, wRC+, xWOBA, and fWAR. No matter where you look, he was their most valuable player. Quite the feat for a player who was league average in both 2018 and 2019. He’s always been a bit of a bruiser really, ranking in the 86th and 92nd percentile in exit velocity in 2018 and 2019, respectively. Yet, that’s never quite translated to above average on-field production. Until the sprint season, that is.

Plate Discipline

Let’s start with plate discipline. When I see a player in the bottom 5% of strikeout rate for the last three seasons, I immediately look here.

On the aggregate, not much has changed. +4 run value in 2019 to +7 run value in 2020. But when we zoom in and break it down by zone, the song changes its tune. Hernández decreased his Swing% on pitches in the heart of the zone from 77% to 67%, resulting in a net +13 change. It’s always fascinating to see a hitter have more success from swinging less frequently in the heart of the zone.

In fact, on pitches which Baseball Savant defines as meatballs, his Swing% decreased from 81.1% in 2019, to 64.9% in 2020. Of players with a minimum of 150 plate appearances in 2020, that 64.9% meatball Swing% ranks in the 8th percentile. In other words, 92% of players in the league swung at meatballs at higher rates than Hernández. That’s a pretty significant change for a hitter who needed a serious revamp in his approach. That change in approach showed direct feedback in terms of results. His xwOBA on pitches in the heart of the zone went from .394 in 2019 to .561 in 2020. Whatever they’re preaching in Toronto really paid off throughout the shortened 2020 season.

Launch Angle

Let’s start off with some good ole data visualization by looking at Hernández’s launch angle distribution between 2019 and 2020.

Well, that’s certainly interesting. Most of the change in LA distribution comes from balls hit at a launch angle higher than 32 degrees. When you hit the ball as hard as Hernández, this change will most likely be very beneficial. Fewer balls hit at less than 0 degrees and more at greater than 32? I like the sound of that. Even a mere 5% change can completely alter a hitter’s results. To further confirm why this change was beneficial, let’s check out how hard he hits the ball when it is hit greater > 32 degrees.

In both 2019 and 2020, the exit velocity is greater than Hernández’s overall average for the given season. Even without seeing these numbers, it is quite promising for a hitter who hits the ball as hard as the 28-year-old to change his batted profile in this fashion. Despite this change, he was able to decrease his Pop-Up% from 8.8% to 3.9%. Again, this is a great sign. Plate discipline and changes in batted ball profile work hand in hand. This is how I look at making adjustments as a hitter. Broadly, you can do one of two things (or both):

1. Make physical adjustments to compensate for pitches/location that are glaring weaknesses in your profile.

AND/OR

2. Make an approach change to better fit for the strengths and weaknesses in your swing.

If you’re able to do both, the results can often lead to a breakout that looks like the one Hernández just experienced.

The Swing

There must have been some mechanical adjustments too, right? Before diving into it, see if you can find anything yourself. The first clip is an absolute bomb from Hernández in 2019 against Andrew Cashner. The second? That is another Hernández tater, but it’s from 2020 against Josh Fleming. Go ahead and watch these and search for the changes from multiple angles.

The first adjustment has become very popular throughout professional baseball. Rather than controlling your bat with your upper body and starting from a stiff position, Hernández opted for letting the bat rest on his shoulder. While both are static positions, one allows for a much smoother transfer of energy. You can’t see it in these clips, but in 2020, Hernández actually has his hands rested close to his hips at times as well. He’s seemed to put a priority on being relaxed throughout the upper half of his body.

The angle here isn’t exactly one-to-one, but the takeaways are plentiful nonetheless. These still-shot photos were captured right before Hernández starts his forward drift. This position is important to note to evaluate the outfielder’s stature at peak leg lift. Not only is he lifting higher in 2020, but he is also internally rotating his lead hip much more.

To understand this feel, align your feet right outside your hips while standing, then try to point either big toe towards your midline while keeping your pelvis in place. The more you are able to rotate, the more mobile your hips are in terms of internal rotation.

Hernández is taking advantage of his impressive mobility by increasing the magnitude at which he is lifting and rotating. This gives him more time to adjust to off-speed pitches because he now has more control of his body. When you begin to drift forward in your swing and shift the position of your pelvis relative to your back leg, it is extremely important to drift with control. As control of your body decreases, the variance and volatility of subsequent launch angle increases. This is bad. Moving multiple body parts at once with the intention of hitting a baseball as far as possible is very difficult. That’s why taking advantage of all the strengths of your body is crucial to maximizing the results of your swing.

There’s two things worth noting about the above photos. First is Hernández’s ability to maintain connection throughout his swing in 2020. Connection is that L shaped angle you see him create with his bottom arm in the photo on the right. In 2019, that arm is almost completely straight at the same point of the swing. If you tried to push any object with any sort of authority, you would want to keep your arms tight to your body, not far away. The same concept applies to the swing. A lot of old schoolers refer to this as staying inside the ball. It’s an external cue that almost forces your arms to not cast too far away from your shoulders.

The next part is a bit more difficult to notice with the naked eye, so I’ve cut both swings up for you to see. First, we have Hernández in 2020 against Fleming.

Next, we have him against Cashner in 2019.

It’s beautiful, really. Both homers were absolutely obliterated. However, there is a slight difference. In 2019, there’s a very pronounced dip in the outfielder’s body and stature after contact. Focus on his belt and you’ll notice it. In 2020, it’s much quieter and more explosive. Immediately before and after contact, his hips are in almost the same position relative to the ground, and all he’s done is rotated them. Many hitters can be successful with the 2019 hip drop, like Adrian Beltre. I just don’t think this movement was optimal for Hernández’s transfer of energy. The slight adjustment has quieted him down for the better.

Maybe Hernández won’t quite maintain a full season of 143 wRC+ output in 2021. Notable projection systems such as ZiPS has him at 115 and Steamer has him regressing back to 102, which would make the outfielder a barely-above-average outfielder this season. I guess the projection systems aren’t too sold on him yet. The K/BB ratio is still a bit concerning, but do projection systems control for these incredible adjustments in swing mechanics? No, they don’t. If I’m betting on the over/under 115 wRC+, I’m certainly taking the over for the 28-year-old. Thanks to Hernández and others, the arrow is pointing directly up for the Blue Jays in 2021 and beyond. The whole lineup is exciting. Look for Hernández to continue raking with the rest of those young studs.

Follow P365 MLB Analyst Estee Rivera on Twitter! @esteerivera42

Follow us on Twitter! @Prospects365

Featured image courtesy of the respective photographer and the Toronto Star