Meet Rex & Lex: The two sides of Dexter Fowler

It’s not hard to see that Dexter Fowler is more comfortable as a right-handed batter than as a left-handed one. In fact, it’s so easy that one need not even watch Fowler hit in order to see it. Check out his career stats from each side of the plate:

Dexter Fowler, Platoon Splits, Career

If one considers Fowler as two distinct hitters, they’re both valuable guys—although keep in mind, Fowler has spent the bulk of his career in Colorado, so that .760 OPS as a left-handed hitter is somewhat shy of inspiring. They’re vastly different though. Rex Fowler is a true leadoff man, a line-drive, gap-power guy with excellent control of the strike zone, including a high contact rate. Lex Fowler is a longer-swinging, more powerful hitter, more dangerous in one sense, more vulnerable in another, prone to empty swings.

Fowler hit exclusively from the right side until less than a month before he was drafted, and it shows. He’s an excellent athlete and has built a left-handed swing that allows him to avail himself of his athleticism—his speed, his long arms and legs, and his natural strength. It’s a swing that often struggles to catch up to a good fastball, though, and it isn’t built to attack anything up in the zone. You can see it in that ugly career strikeout rate from the left side. Fowler did yank a grand slam on Sunday, part of a blowout Cubs win over the Twins, but it was his only hit of the game, and he was left hitting .218/.290/.382 as a lefty this season.

That would hurt under any circumstances, but this season, it’s killing Fowler. He’s hitting just .238/.315/.392 overall. Why? Because Fowler is having to call upon Lex more often than ever, leaving Rex to twiddle his (more talented) thumbs. Prior to 2015, Fowler had faced lefties in almost exactly 30 percent of his career plate appearances. This season, it’s precisely 16 percent. It has to feel strange for Fowler, who’s hitting only marginally worse than he always has, really, but is seeing ugly statistics pile up.

So goes life with the Cubs. (Ask Starlin Castro, your friendly neighborhood lightning rod, whose 14-percent frequency of batting with the platoon advantage is the lowest among all batters with at least 200 plate appearances, and third-lowest among those with at least 100 plate appearances. Castro has come to the plate 285 times.) They’ve faced left-handed pitchers in 16.9 percent of plate appearances this season, the lowest percentage in baseball. The Pirates have faced the second-fewest, at 18.8 percent.

On the other end of the spectrum, the Indians, Astros, Rangers, Twins, and Royals have each faced southpaws in at least 30 percent of all trips to the plate. Speaking of those Astros, by the way, they traded Fowler to the Cubs in January, and received in return Luis Valbuena. It’s been an equally strange season for Valbuena, who has 17 home runs but a hideous .262 on-base percentage. The explanation is from the same song, but a different verse. Coming into 2015, Valbuena was a .235/.320/.360 career hitter against left-handers. That isn’t bad, but it’s also reflective of the fact that he was used carefully, protected from many southpaws. He saw lefties in only 15.1 percent of his plate appearances over the first seven years of his career.

This season, Valbuena is facing lefties more than twice that often. Of his 259 total plate appearances, 83 have come against them, and in those 83 times up, Valbuena is batting .120/.193/.293. His bizarre season is the result of his hitting exactly the way we would have expected him to hit against right-handers (.215/.290/.494, with an insanely low BABIP), but brutally badly against lefties, whom he’s suddenly forced to face much more often.

There’s a common thread at which to tug here. Chicago and Pittsburgh share the NL Central. Houston and Texas are both in the AL West. Minnesota, Cleveland, Kansas City, all AL Central. Here, then, are teams being pulled toward the extremes of platoon-split breakdowns by the unbalanced schedule they all play. Let’s briefly examine how that’s happening, to what extent it will continue, and whether we should care.

First of all, you should know that lefties are awfully scarce creatures this season. Only 24.9 percent of the league’s plate appearances this year have come against them. If that number holds (will it? Who knows?), it will be the third-lowest percentage in our 45-plus years of detailed data on platoons, after 2000 and 2001. Lefties have started 23.3 percent of all games on the mound, which would be the lowest share since World War II.

With fewer lefties to go around the league, there seems to be an increasing clustering of them. Maybe some teams are valuing left-handedness in a way that others aren’t. Maybe the phenomenon is random, just the way things are shaking out. One way or another, though, it’s happening. The Mariners and Angels have started lefties 65 times between them. The White Sox have four left-handed starters who have started at least eight games. Nine teams don’t have even one such starter. Six don’t have a lefty who’s started even five times. The Reds, Brewers, and Padres all have gone the entire season, to date, without giving a start to a southpaw.

I think what we most need to know about these numbers is: should they be affecting our forecasting of the rest of the season, or should they be coloring our reading of the games played to date? In other words, is this kind of thing truly bound to even out, to whatever extent, or is it a real phenomenon we ought to build into our projections for the second half of the season?

MLB Teams, Percentages of PA Facing LHP, 2010-15: Spread and Standard Deviation

The answer is mostly the former. There’s some evidence that the percentage of lefties faced by each team has varied more over the last few years, but the current spread would represent a 60-percent increase over even the last three seasons.

That said, there will still be teams who see significantly more left-handers than others do. The Reds might trade Johnny Cueto (and even, perhaps, Mike Leake) by July 31, and call up a lefty, but they’re likely to have a right-leaning pitching staff all season. Ditto for the Brewers, who have made a point of this over the last few years.

This raises some really interesting questions, like whether or not the Cubs and Astros ought to be blamed for not foreseeing that the players they were acquiring would prove ill-suited to their respective opponent sets. (Not that it’s that simple. It’s perfectly possible—probable, even!—that each side saw that downside in the player they were bringing aboard, but felt the ways in which those players were good fits outweighed the issue. Maybe they’re even right about that. Time will tell.) It also invites us to wonder whether guys like Fowler and Valbuena are doomed to fail with some teams, but well-positioned to succeed with others. It will often be difficult to tell, heading into a season, which teams will see lots of lefties, and which will see few, but it seems as though that might be a valid consideration when weighing an acquisition. It’s definitely an indicator we need to keep an eye on when evaluating in-season statistics, both because it’s something that can change based on schedule quirks, and (more importantly) because it’s crucial information when attempting to fairly evaluate a player.