Why does Josh Naylor keep facing lefties?

I love Josh Naylor, but I do not love seeing Josh Naylor face so much left-handed pitching.

Since Naylor entered Major League Baseball at the age of 22 in 2019, he has been among the worst hitters in the league against southpaws. Of 454 players with at least 170 plate appearances against left-handed pitchers during that time period, he is tied for 419th in wRC+ at 54. To give some context, that is exactly Austin Hedges’ career wRC+ as of this writing. Thankfully, over the past 569 plate appearances against right-handed pitchers, he has a 131 wRC+.

To summarize: Against righties, Josh Naylor is a potent threat in the Guardians lineup, and against lefties, he’s Austin Hedges. So why don’t the Guardians platoon him? I suspect the answer has three parts to it.

First, Naylor is still only 25 years old and has only 1,181 plate appearances in the majors, 283 of those against lefties. This is still a relatively small sample size for a relatively young player to use to conclude that he cannot improve against lefties. For example, Daniel Vogelbach and Naylor have very similar career numbers against left-handed pitchers in a similar number of plate appearances. Vogelbach, however, is 30 years old and there is a much lower chance of any significant improvement from him there at that age and level of experience, so he is consistently platooned while Naylor is not ... yet.

Second, Naylor had decent numbers against southpaws in the higher levels of the minors. In Low-A, Naylor put up a .635 OPS in 142 plate appearances against lefties, and in High-A- to Double-A he managed a .665 OPS in 106 plate appearances. These numbers are still significantly better than his .535 OPS against left-handed pitchers in the bigs, but you can see that he is at risk of a platoon already. However, in his second season at Double-A (still only 21 years old), he managed an .872 OPS in 163 PA’s against lefties, and in Triple-A and the majors at the age of 22, he posted an .849 OPS in 127 plate appearances against them.

If one compares these numbers to two recent left-handed hitters who were heavily platooned in Cleveland — Lonnie Chisenhall and Tyler Naquin — one will quickly notice that both Chisenhall and Naquin consistently saw .100-.150 points of difference between their OPS against righties and lefties, with the latter generally running in the low .600’s for most of their time in the minors for both. Naylor showed promise in the ability to hit left-handed pitching that these other quickly-platooned lefties did not.

Third, I am sure that Naylor’s positional limitations play a part in the decision to continue to allow him to face left-handed pitching. Taking Naylor out requires Francona to put another player as a designated hitter if Naylor is playing there, eliminating the ability to move that player to a different fielding position if need be. Additionally, bench players are often times training to play one of the three outfield positions or another infield position, so sending them to first base is also not usually a natural move. Gabriel Arias, for example, is more than capable of playing first, but his instincts there are not as natural as they will be at second, short, or third. On the Guardians roster, in particular, Josh Bell is a poor defender at first base, so being able to keep Naylor there late in games is especially beneficial for defensive purposes.

The trouble with platoon conversations is that we are often times dealing with very small sample sizes. With that said my preference would be to continue to give Naylor chances to hit left-handed starting pitchers but to be aggressive in trying to pinch-hit him out against left-handed relievers late in games, especially in games where runs are at a premium and there are runners on base.

In 74 plate appearances against lefties in the fifth and sixth innings, Naylor has an 86 wRC+. This indicates to me that he is a little better against pitchers he’s had a chance to see a few times. In contrast, in the seventh and eighth innings, he has a 56 wRC+ against left-handed pitching. Now, in a mere 29 plate appearances in the ninth inning against lefties, he’s had 11 hits including two doubles and a homer for a 190 wRC+, so my theory falls apart a little bit there. Still, given the evidence of my eyes, I’m going to conclude this is small sample size noise, and Josh Naylor vs. lefty specialists from the pen is, in general, a bad matchup for the Guardians.

In looking at pitch data, I can tell you that Naylor sees about .10 more pitches per plate appearance against left-handers than he does right-handers and he swings and misses at a significantly higher portion of pitches down and away from left-handed pitching (34% of his swing and misses, as compared to only 18% of his swing and misses against righties). Easier said than done, but Naylor may benefit from being more aggressive on pitches middle-in earlier in counts against left-handed pitchers and trying to lay off more pitches down and away.

If there are runners on and the Guardians are in need of insurance runs or runs to catch up, Naylor should be pinch-hit for against left-handed relievers in the seventh inning and later if possible. He should continue to get regular repetitions against left-handed starters, say, facing every other lefty the Guardians see until we get a larger sample to analyze if there is any improvement to be had when facing them.

If there is no improvement by the All-Star break, I believe it will be time to platoon Naylor whenever possible to maximize his offensive talents and give other right-handed bats a chance to help Cleveland against left-handed pitching.