Platoons are common these days. Most righties can hit lefties better, and most lefties can hit righties better. In some cases, the difference is so extreme such that a partner is necessary to face the same-handed pitcher. This is a chronicle of those who have the most limited exposure to same-handed pitching.
A little context. I went to Fangraphs and pulled the basic data for all players (excluding pitchers) against left-handed pitching and right-handed pitching. I did not have a minimum for plate appearances. I wanted all the batters even though there will be plate appearance limitations for analysis, as you'll see later. There will be a Tableau visual you might want to investigate. Also, I did not exclude switch hitters. Those players face both kinds of pitchers with regularity and usually won't be platooned much. I'm sure there are exceptions.
For analysis purposes, I'll limit the data to those who have at least 100 plate appearances. It's an arbitrary cutoff, but with the extensive amount of plate appearances necessary to find some signal in the noise, any cutoff is arbitrary. In order to rank players by the amount they have been platooned, I calculated the percentage of plate appearances each player has faced against righties and lefties and took the difference. Those with the highest percentages are the ones who have faced RHP the most; those with the negative percentages have faced LHP more*.
*As you would expect, there are far more players with a higher percentage of PA against RHP since RHP are more common than LHP.
5. Dustin Ackley (89.1 percent difference)
After a decent second half last year driven by a torrid pace in July and August, there were rumblings that Ackley figured something out. He squared the ball up better after the All Star break, suggesting that maybe some of his torrid pace was for real. He ended the year with a 97 wRC+, which isn't all that bad when combined with presumably adequate defense in left field.
The Mariners, perhaps, were not convinced. Ackley has faced righties almost exclusively this year, but his production has tanked. His walk rate and strikeout rate have each gone the wrong direction, and his wRC+ stands at 54. His platoon split is not that big (Career numbers: 80 wRC+ vs. LHP, 93 wRC+ vs. RHP), but certainly he has performed better against righties in the past. Whatever line drive ability he showed in the second half last year has not manifested this year. Given Ackley's occasional fluctuations in line drive rate, it is possible for a rebound.
4. David Murphy (93.0 percent difference)
Murphy has been a platoon guy for quite awhile now; he has faced righties almost 3.5 times more than lefties for his career. His career platoon split is fairly substantial (113 wRC+ vs RHP, 71 wRC+ vs. LHP).
Murphy is currently bashing righties with a 136 wRC+ and a miniscule strikeout rate. In fact, Murphy's 7.9 percent K rate is tied for fourth-lowest among hitters with at least 100 PA. Murphy's exposure to lefties has been severely limited. He's faced them all of four times. Everything is going according to plan here.
3. Smeth Sith...Seth Smith (94.8 percent difference)
Smith is even more of a platoon player than Murphy. Smith has faced righties about 5.2 times more than lefties in his career and has a bigger platoon split than Murphy (123 wRC+ vs RHP, 63 wRC+ vs LHP).
Smith had something of a breakout last year with the Padres; he leveraged a fantastic walk rate, the lowest strikeout rate of his career, and a significant percentage of plate appearances against righties to produce a 133 wRC+ and snag a contract extension from last year's Padres management, who are most definitely not this year's Padres management. Smith is a Mariner, not a Padre.
Smith's platooning ways have continued with the Mariners. His walk rate is reduced and his strikeout rate has increased, but he is hitting for more power. His 125 wRC+ is fairly well in line with his performance last year.
2. Conor Gillaspie (94.9 percent difference)
Gillaspie appears as though he was platooned from the beginning. His platoon split for his career is pretty awful -- 36 wRC+ vs LHP and a 106 wRC+ vs RHP. He's faced lefties only 186 times in his career and has terrible walk and strikeout rates against LHP.
Unfortunately, Gillaspie's walk rate has declined again so far, and his strikeout rate has increased from last year. He has not hit righties as well this year; his overall wRC+ of 83 this year is clearly worse than 108 last year.
1. David DeJesus (95.5 percent difference)
As a Royals fan, I have fond memories of DeJesus during a time which most fans would prefer to forget. Those memories do not include DeJesus as a platoon player. Yes, his career 118 wRC+ against RHP is better than his 78 wRC+ against LHP. However, during his time as a Royal, his platoon split was nothing to worry about. He even performed better against lefties one season.
As his career went on, he became more of a platoon player. He's been a member of the Rays for the past 2+ years, and his platooning has been even more evident since then. DeJesus has a grand total of 12 plate appearances against lefties over the past two years. That his exposure has been so severely limited against lefties is quite amazing.
DeJesus has gotten out to a hot start this season with a 157 wRC+. Much of that is driven by BABIP luck, but he appears to be hitting the ball harder this year. His line drive rate and rate of hard contact are up, which are helping to cover for his decreased walk rate.
Overall, it's a mixed bag. Ackley and Gillaspie are not performing well. Murphy, the Sith Lord Smith, and DeJesus are performing pretty darn well. Ackley is reaching unprecedented levels of platoonity, and Gillaspie is still relatively young. Murphy, Smith, and DeJesus are grizzled vets. Ackley and Gillaspie have a history of not performing all that well. The others have a history of performing well. Don't read too much into the age thing.
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