When the St. Louis Cardinals signed Dexter Fowler to a five-year, $82.5 million contract following a 2016 season which was arguably the former Chicago Cub’s career best, the team expected that they had solved concerns over the previous few seasons regarding the center field position. From the 2011 trade deadline through 2014, the starting job had been held by Jon Jay (with a brief cameo from Peter Bourjos in early 2014), an adequate if mostly unexceptional player, but when Jay’s performance dramatically fell in 2015, the job went to Randal Grichuk. And then in 2016, Grichuk battled injuries and defensive inconsistency, with many theorizing that Grichuk would be a better fit in left field. Following Matt Holliday’s departure, Grichuk could move to left, but such a move would need a corresponding center field move to make it worth the team’s while. Signing Dexter Fowler was that move.

The assumption made by the Cardinals was that Fowler would provide above-average offense and serviceable defense. The latter was the more obvious question, as prior to his two seasons at Wrigley Field, Fowler’s defense had been Worst Defensive Center Fielder in Baseball Not Named Matt Kemp-level bad, but at Wrigley, Fowler’s defensive metrics started to veer more towards average (it is very rare for a player to substantially improve at defense, but improved defensive positioning was often cited to explain Fowler’s gains). And while 2017 Fowler did hit well when healthy, he had his third-worst season defensively in center field of his career. Meanwhile, the emergence of Tommy Pham, who mostly played in left field in 2017, in conjunction with the acqusition of Gold Glove-winning left fielder Marcell Ozuna, created an outfield shuffle which put Pham in his natural habitat of center field while Dexter Fowler switched to right field.

A residual effect of Dexter Fowler in right field arguably should have been an ability to focus on his offense rather than worrying about his shortcomings at the more critical defensive position of center field. I’m not sure that I actually believe this argument, but I certainly wouldn’t have argued the opposite–that Fowler moving to right field was a recipe for an offensive free-fall. And yet, through roughly one-fourth of the 2018 season, Dexter Fowler has been a disaster at the plate.

It’s partially bad luck–partially. Fowler’s .312 xwOBA entering this weekend’s series against the Philadelphia Phillies, while noticeably higher than his .259 wOBA, is hardly a paragon of offensive virtuosity. Among 168 qualified hitters so far in 2018, .312 would rank tied for 118th with JaCoby Jones, a player I’m only fairly confident isn’t the former NFL wide receiver. This year’s results suggest Fowler is atrocious; this year’s process suggests Fowler is better, but still a diminished version of his former self.

Fowler, of course, is a switch-hitter. For his career, Fowler is slightly better against lefties than righties, though the split is (expectedly) not that pronounced compared to most single-sided batters (117 wRC+ vs. lefies, 107 wRC+ vs. righties). However, the story has changed a bit since Fowler joined the Cardinals–he was better against righties in 2017 (128 wRC+ vs. 100 wRC+) and has been considerably better against righties in 2018 (89 wRC+ vs. RHP, -24 (as in negative 24) wRC+ vs. LHP).

Make of these small sample sizes what you will–I’m not trying to really draw any major conclusions here, though I would ultimately probably settle on “Dexter Fowler is whatever he is, roughly, against any handedness pitcher and his defense is never going to be great, even in a corner spot”. While Fowler is more personally charismatic than the previous off-season’s big free agent signing, Mike Leake, he is perhaps even more boring in terms of on-field results. He’s…okay. Perhaps the Cardinals would mulligan that signing if they could, but they can’t, and it’s in their best interest to use Fowler in whatever way most benefits the team.

And this is where Harrison Bader comes into the picture.

Harrison Bader was hyped (in a loose version of the term) as a fourth-outfielder type, somebody enough in the mold of Randal Grichuk that the Cardinals could justify trading away the actual Randal Grichuk for a relief pitcher. But Bader has looked very strong since being promoted to the big league team early in the 2018 season, and his total wRC+ stands at 116. He has arguably been a bit lucky at the plate, with his current batting average on balls in play standing at .333 (Bader is fast; he’s not that fast), but his xwOBA still stands higher than Dexter Fowler’s. And defensively, Harrison Bader continues to look like everything many fans expected Peter Bourjos to be when the Cardinals acquired him.

But unlike Fowler, there is little question of where Bader stands in terms of platoon splits. The sample size disclaimer remains in full effect, but the results are absolutely jarring–against righties, Harrison Bader has a wRC+ of 48. Against lefties, it is 202. Against righties, Bader is worse than 2013 Pete Kozma at the plate. Against lefties, Bader is better than any Albert Pujols season.

These are extreme splits, and while the gap is probably a bit exaggerated thanks to lack of data, they do follow along with his minor league career. In 2017, in Memphis (where he had 479 plate appearances), Bader had a OPS against left-handed pitching of 1.234, versus .704 against righties. He spent most of 2016 in AA Springfield, where he OPSed 1.485 against lefties and .697 against righties.

Harrison Bader has hit like a superstar against lefties. Will he do this in the Majors in the long term? It’s hard to say, but given his defensive prowess, it’s not hard to imagine he will be a stronger option than Dexter Fowler. This plan can also conceivably allow Tommy Pham occasional days off–Pham has actually been a slightly better hitter against righties throughout his career (to a small enough extent that I’m more or less under the assumption he is fairly split-neutral, but still)–while Bader plays in center field and Fowler plays in right field.

Last night, Harrison Bader pinch-hit for Matt Carpenter to take advantage of Bader’s platoon advantage. While Carpenter has been moved down the batting order in recent days, Mike Matheny has enough faith in his bat to keep him in the lineup, and yet still went to Harrison Bader. It is obvious that the Cardinals realize what Bader is capable of doing against left-handed pitching, and it is overdue for this to be reflected in the starting lineup.