Trying to Understand Cesar Hernandez

This weekend Cesar Hernandez hit two home runs. Two is such a small number in the context of baseball, and most small events like this could be explained as small sample size noise. However, these home runs brought Hernandez to 3 in 12 games. This is Hernandez’s 5th major league season, and in the previous 4 he hit 8 home runs total. The spike is noticeable in the ongoing confusion that is Cesar Hernandez.

The introduction of StatCast has brought a larger voice to the concept that hitting the ball in the air is better than hitting the ball on the ground. This is not a new idea to anyone who has studied basic mechanics and specifically ballistics. The 2016 data bears this out too.

Batted Ball Type AVG ISO
Ground Ball .239 .019
Fly Ball .241 .474
Line Drive .689 .210

So how does this tie back to Cesar Hernandez? Here is Hernandez’s batted ball data in his time in the majors:

Now this is only part of the story. Making an adjustment is not no consequence change. To get the ball in the air, Hernandez had to change not just the angle of his contact, but where on the field he was hitting the ball to.

Where you hit a baseball matters for a variety of reasons. Most hitters have more power to their pull side, but it makes them more susceptible to shifts. Hitting the baseball up the middle is going to be a hit more often because of fielder placement, but the batter is also aiming for the deepest part of the ballpark. Hits to the opposite field make it difficult to shift a hitter, but it takes a lot of raw power to hit a baseball the opposite way.  Here are is the average BABIP and ISO for batted ball direction.

Ball Location AVG ISO BABIP
Pull .340 .294 .288
Center .340 .164 .315
Opposite .317 .149 .298

So by pulling the baseball more, Hernandez is going to give up some batting average, but it allows him to tap into his raw power. It is unsurprising, then, that until his game opening home run on Sunday, all of Cesar’s career home runs had been pulled to right field. The Sunday home run was the first that he had pulled to left field while batting right handed. Pulling the baseball has not just led to more home runs for Cesar, he also has been able been able to hit for triples down the right field line and into the right center gap.

A big problem in projecting out Cesar Hernandez in the major leagues has been his walk rate. With the exception of his 2011 season, where the Phillies had to aggressively skip him over Lakewood due to 40 man status, Cesar has always had a good walk rate. There are two fairly obvious parts of a walk rate, the hitter and the pitcher. The hitter has to not swing at 4 balls outside the strike zone without striking out or putting the ball in play. The pitcher has two throw 4 balls outside of the strike zone before the at bat ends. Pitchers avoid the strike zone for a variety of reasons, but the one we care about for this purpose is that they are trying to avoid giving up extra base contact to the hitter. Against a player with little power, the worst case scenario is maybe a double into the gap. Against a better hitter like say Bryce Harper, the result is much more devastating. Cesar’s highest isolated power in the minors was .146, but more telling is that even with a power surge in 2016 and into this season, his career isolated power is .088. Ath time of writing this, that was the 26th lowest among all active players with at least 1000 career plate appearances (298 qualified). There is a general correlation between power and walk rates, where the lower the power output is, the lower the walk rate (it also helps that elite players tend to hit for at least some amount of power). Here is how it worked out for the 2016 season.

Cesar and Brett Gardner are the outlier spike at around .100 ISO. This definitely places Cesar as an outlier, but he also is now at nearly 1,400 plate appearances of a 9.2% BB%, which is enough to put forth the claim that this is somewhat real. At very least, his increase in power output will help offset any regression that was in his previous skill set.

So that covers the offensive side of the Cesar mystery, and it is a story that is not entirely uncommon, as attitudes have changed on previous conventions due to the influx of easier to process stats and outside hitting coaches. He is just hitting for more power, because he has adjusted how and where he is hitting the ball to hit for more power.

As for the rest of what else fueled Cesar’s rise, it is certainly not his baserunning, which continues to be maddening. It is his glove, which has gone from a bit of a liability to a definitive plus. He does not have a strong arm, and he can be prone to mistakes, but he does use his speed well to cover a good amount of ground, and he is willing to take some risks on throws, relying on an accurate arm to limit damage.

It is still tough to see Cesar being a star level player, but he was a 3-4 win player last year, and much like Odubel Herrera’s transition from unsustainable to sustainable, the introduction of more power to his game could make Hernandez the Phillies’ second baseman of the future, and not just a bridge to the future.

Batted Ball Data From Fangraphs