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David Peralta took a step forward in 2018

By at least one metric, Peralta was the most improved hitter last season.

MLB: Colorado Rockies at Arizona Diamondbacks Joe Camporeale-USA TODAY Sports

Going into the offseason, the Diamondbacks were probably going to lose Patrick Corbin and AJ Pollock. Re-signing the center fielder or pitcher wasn’t completely out of the question, but it didn’t seem entirely likely. Not only did they not re-sign either, but they also traded away Paul Goldschmidt, the face of their franchise who is second on the team’s all-time bWAR list. With all the players that have left, the best remaining might be David Peralta. If he’s not, he’s at least their best position player. That is, if he can repeat his 2018.

At 30, Peralta put in a career year. After totaling 2.1 fWAR in the previous season and a half of playing time, Peralta nearly doubled his value at 3.8 fWAR. His 130 wRC+ was his highest since his 137 mark in his sophomore season in 2015. He also cracked 30 homers for the first time.

At first glance, it might not appear that Peralta’s step forward is for real. For one, his year was inconsistent. Through the end of April, Peralta hit like Khris Davis. In May, Peralta hit like Chris Davis. His August was the best month of his career. His walk rate of 7.8 percent didn’t budge from his career average. He struck out a respectable 20.5 percent of the time, but he’s always been a smidge above average at avoiding strikeouts. He’ll likely not homer on 23.4 of his fly balls this season, but Peralta certainly hit the ball with more authority and with more consistency.


Peralta’s hard-hit rate increased by 16.8 percentage points. Hard-hit gains meant less in 2018 than they have since the stat has been tracked. The correlation coefficient between hard-hit rate and wRC+ was 0.48 in 2018 (among qualified hitters). Since 2002, it’s 0.57. Hard-hit rates still mean something and 16.8 points is a lot. No other player had a greater jump in hard-hit rate in 2018. Not all players benefited from an increase in hard-hit rate, but Peralta sure did.

One of the things that contributed to this increase was that Peralta became much better at hitting sliders. Being able to crush sliders is going to be a nice skill to have in this new era of baseball when sliders are more common than sinkers. Peralta saw nearly 100 more sliders than he had in any previous season. According to pitch values, there were only five batters who hit sliders better than Peralta, and two of them were MVPs.

David Peralta Against Sliders

2014 1.6 1 .255 .489
2015 0.7 0.31 .113 .355
2016 -2.4 -3.3 .143 .286
2017 1.3 0.44 .111 .383
2018 9.2 2.71 .366 .656

A year-to-year increase in performance against sliders might be more of an anomaly than an indicator of change. Yes, he hit 9 of his 30 homers against sliders this year. In his previous four seasons he had only homered off of five sliders, so that seems like there’s been an adjustment.

It’s just difficult to pin down what that adjustment is. It could be that he’s moved his point of contact further in front of the plate though His swing looks the same as it did in 2017. His discipline stats against sliders didn’t change in an obviously meaningful way. Him crushing sliders might just be indicative of him crushing everything.

While we can be skeptical of this change, it will be something to monitor come Opening Day. If Peralta has figured out how to hit sliders better and he can continue to square the ball up consistently, it should help him bring his success into 2019.

Kenny Kelly is a writer for Beyond the Box Score and McCovey Chronicles. You can follow him on Twitter @KennyKellyWords.