As a team, Diamondbacks batters performed better when they swung at the first pitch. In 2021 through 20 May, BABIP was better (.301 vs .268) and RBIs per PA was better (.151 vs .093). Albeit that if the pitcher misses the plate the batter is better off not swinging.
Let’s compare the first 45 games of this season to 2020, when there were 60 games. That comparison showed that while the RBIs per PA comparison was nearly the same (.151 vs .093), the BABIP comparison was different. In 2020, BABIP was the same whether of not the batter swung at the first pitch (.283 vs .282). This suggest that first pitches are more hittable than later pitches.
The following table shows 3 batters who performed better (BABIP and RBIs per PA) when they took the first pitch, and 6 batters who performed better when they swung at the first pitch.
What about when the first pitch is a fastball?
This season, Eduardo Escobar hit one homer on a first pitch fastball. What is remarkable is that when he fouled off a first pitch fastball (which happened 12 times this season), in three of those PAs he hit a homer. These facts confirm that Escobar has found great success when he swung at a first pitch fastball. The other Diamondbacks who hit one homer on a first pitch fastball were Carson Kelly, Pavin Smith, and Josh Rojas.
There are 9 batters with at least 10 swings at first pitch fastballs. For those 9 batters, let’s look at their swing percentage and their wOBA when they swung. And to add context, let’s compare those numbers to last season.
The following graph shows those 9 batters. When batters had similar year-to-year changes, their results are the same color.
First the good news. Calhoun, Kelly, and Locastro are swinging more often with significant improvement in their wOBA. By a large margin, Kole Calhoun is the best at hitting first pitch fastballs.
Then the blah news. Ahmed, Cabrera, Rojas, and Walker are swinging more often at first pitch fastballs with no significant improvement in wOBA except maybe Walker.
Escobar is a conundrum, but it his results improved. His OPS+ improved from 61 in 2020 to 103. This season he hit a homer in 5 of his PAs when the first pitch was a fastball.
This season, the graph shows Peralta’s wOBA dropped more than the other 8 batters, albeit a lot of could be because of the pitchers he faced. In PAs with a first pitch fastball, Peralta’s best result was a single (which happened 4 times). He swung less often at first pitch fastballs, which was a good thing because when he swung his wOBA was lower.
Let’s broaden our focus to all of Peralta’s PAs this season. This season his BA and OBP are lower, while his SLG and OPS are higher. His remarkable improvements were his 5 triples so far (only 1 last season), his improved SO% (reduced from 20.6% to 15.5%), and his increased BB% (increased from 6% to 8.1%). Perhaps instead of a problem, David Peralta as a batter has changed: a better eye at the plate and more power when he hits the ball.
There is an additional reason why swinging at first pitch fastballs is important. My view is that it is only a matter of time until MLB takes action to reduce the use of sticky substances that make it possible for pitchers to increase the spin on their fastballs. When that happens fastballs will become more easily hittable. This is an opportunity for the Diamondbacks to be the best at hitting first pitch fastballs so they can benefit when change happens.