Edmundo Sosa’s Next Step

Edmundo Sosa is not a bad fastball hitter by any means. In fact, he had a .341 wOBA against the pitch in 2022, which was his highest wOBA against any pitch group. Still, his average exit velocity against fastballs (84.7 mph) actually dragged down his overall exit velocity (86.7 mph). That’s right. His lowest exit velocities came against fastballs. In fact, the reason that he was even an above average hitter last season was because he hit well against breaking and offspeed pitches. Generally, those are the more difficult pitches to hit. Now, exit velocity isn’t some kind of end-all-be-all statistic for hitting prowess, but Sosa’s exit velocities of 88 mph against breaking pitches and 87.5 mph against offspeed pitches are markedly higher than his exit velo against fastballs. In fact, Sosa had a higher exit velocity against breaking balls than Nolan Arenado.

This can be looked at in two ways. The first is negative because Edmundo Sosa should be doing better against fastballs. The second is overwhelmingly positive - Sosa would be a complete hitter if he could crush fastballs. The second view is the one that I want to take.

The shortstop had an ISO of just .112 against fastballs. Again, these are the pitches that he should be crushing, yet he showed almost no power against them. He is not exactly a power hitter, but he did hit 12 home runs in 2018 and 17 in 2019 while in the minor leagues. He also had a 93rd percentile max exit velocity of 114.6 mph, so there is definitely more power in his bat than we saw this year.

Sosa had a .182 ISO against offspeed pitches and a .107 ISO against breaking pitches last year, which means that his ISO against fastballs was actually lower than his ISO against non-fastballs. It gets even worse, though, because the 25-year-old’s xISO against fastballs was below .100 (.095).

This is mostly because Sosa was the only player on the St. Louis Cardinals last season (min. 100 PAs) who had a lower exit velocity against fastballs than he did overall. Sosa also whiffed at more fastballs than the average hitter (24.9% whiff rate), while his whiff rates against breaking pitches (31.5%) and offspeed pitches (28.5%) were about in line with the respective league averages. So, not only does Sosa not hit fastballs very hard, but he also swings through them quite often when compared with the rest of the league. That’s not a great recipe for production, especially when Sosa saw nearly 55% fastballs last year.

This is where his production against other kinds of pitches helped him, but when his hit by pitch rate inevitably declines, he will need to make up for that loss in production. Better production against fastballs could certainly help.

Sosa was also the least aggressive against fastballs as compared to other pitches. His swing rates against breaking balls (57.1%) and offspeed pitches (54.7%) were much higher than his swing rate against fastballs (51.2%). This is despite the fact that fastballs were thrown in the zone much more often than other pitches when he was hitting. So, the usually aggressive Sosa dialed back his aggression against fastballs while swinging more freely at pitches that are more difficult to hit and thrown outside the zone more often. Again, that doesn’t seem like the best approach. Perhaps Sosa had less confidence in his ability to hit fastballs well so he was more reluctant to pull the trigger.

Still, fastballs are where hitters make their living. Sosa needs to get better and more aggressive against them if he wants to prove that his above average production at the plate in 2021 was not a fluke.

Not all fastballs are the same, though, and Sosa performed differently against sinkers and four-seamers. Against sinkers, Sosa had an incredible .411 wOBA. However, he also had an extremely low exit velocity of 83.7 mph, his lowest against any pitch. He also had a ground ball rate of 68% and an xwOBA of just .323. Thus, there was a great deal of luck in that .411 wOBA.

On the flip side, Sosa had a worse .347 wOBA against four-seamers, but a better .361 xWOBA, a better (but still not great) 85.4 mph exit velocity, and a better 51% ground ball rate. Even though these numbers could stand to improve, Sosa really needs to work on not beating sinkers into the ground.

If he gets a full season of 83.7 mph exit velocity and 68% ground ball rate against sinkers, he surely would be lucky to finish the season with a wOBA of .323 against the pitch. It is not too surprising that Sosa struggled to make solid contact with sinkers as former VEB and current Fangraphs writer Ben Clemens recently demonstrated. (You can read the rest of his article here)

The key takeaway here? Against groundball hitters, sinkers are an excellent choice of pitch. The hitter tends to hit the ball into the ground and sinkers generally influence launch angles downward. The result is frequently a grounder, which is great for the defense.

Sosa is a great example of this as a ground ball hitter (51.8% GB% in 2021) with a 68% ground ball rate against sinkers. His .411 wOBA against the pitch last year is unsustainable and he will need to learn how to hit more balls off the ground at higher velocities if he wants to have more success against sinkers. If he cannot do this, then his numbers against sinkers will decline significantly next year. A way to do this could be to simply work on hitting fewer ground balls overall so that his swing isn’t so ground ball oriented when he faces sinkers.

Sosa can fly so he has a better chance of beating out an infield single than other hitters, which theoretically doesn’t make ground balls as bad for him as for someone like Yadier Molina or Paul DeJong. Still, Sosa could stand to hit more balls in the air because he is much more of a power threat than he showed last year.

He is not a power hitter, but his near-elite max exit velocity, double digit home run totals in past (minor league) seasons, and higher exit velocities against non-fastballs all mean that he has more in the tank. Harder contact and fewer ground balls against sinkers would lead to more extra base hits and help Sosa have good and sustainable production against sinkers.

Against four-seamers, Sosa has the same problems but to a lesser degree. He still needs to hit them harder (85.4 mph exit velocity) and get them off the ground more (51% GB%). His ground ball rate against four-seam fastballs is right in line with his overall ground ball rate, but a higher average exit velocity, which is certainly achievable, would allow for more power production on balls hit in the air.

Sosa basically had the profile of a slap hitter last year - low exit velocities, lots of ground balls, and lots of balls hit up the middle or to the opposite field. He did well with this profile (104 wRC+), but he was also the beneficiary of lots of HBPs and unsustainable fastball production.

That may be the story for Sosa. He may be a slap hitter long term, and with his excellent defense that is a fine profile for a utilityman. Still, he could become more than that with better results against fastballs. If he can hit curveballs and changeups hard then he should be able to hit fastballs hard too.

Some hitters can struggle with velocity, and Sosa may be one of them. However, improving against fastballs is the best way for Sosa to improve at the plate.

There is a gap between his production on fastballs under 95 mph and fastballs over 95 mph. On fastballs 95 mph and slower, Sosa had a .402 wOBA and a 85.8 mph exit velocity. On fastballs over 95 mph, the shortstop had a .306 wOBA and an 79.7 mph exit velocity. Fastballs with elite velocity are tough to hit and that is clearly true for Sosa.

The right-handed hitter saw 182 pitches at 95 mph or slower and 111 pitches at 95 mph or faster. He clearly needs to work on hitting fastballs with high-end velocity because he saw plenty of them and failed to square them up very often.

Thus, Sosa struggled the most against pitchers with elite velocity. He could still stand to hit sub-95 mph fastballs harder, especially since he will see more of those kinds of fastballs than he will fastballs with elite velocity. The infielder doesn’t need to crush 100 mph fastballs, but he does need to at least be able to hit them semi-consistently. If he can crush the 90-94 mph fastballs then he can afford to struggle more against the higher velocity, so he does need to improve against fastball of all velocities.

It seems that he is a hitter who struggles more with catching up to heat but isn’t fooled by movement.

This is a bit uncommon, but it does give him a clear way to improve. It is probably easier to improve against fastballs than it is to improve against breaking balls, so that is an added advantage for Sosa. Perhaps his bat speed isn’t enough to catch up with velocity or perhaps the higher velocity simply makes it harder for Sosa to see the ball well enough to find the barrel. Either way, a steady diet of fastball training is what he needs this winter.

As I showed before, it is incredibly uncommon for a hitter’s average exit velocity to be dragged down by fastballs. Sosa had plenty of success against the hardest pitches to hit, which is promising. Now he just needs to learn how to crush fastballs. He has more power to tap into and better production against fastballs is the best way for him to tap into it. If he can hit fastballs harder and stop beating sinkers into the ground, then he will reap the benefits in 2022.

This is the key point in his hitting development. He had a nice season last year but inflated production against fastballs and a much too high HBP rate are unlikely to be sustained in 2022. He will need to compensate for that somehow. Hitting fastballs is the way that he can do it.