Odubel Herrera: Rule 5 Christian Yelich

If not for last year's historic crop of rookies Odubel Herrera would likely be, if not a household name, one that most fans would recognize. Even still, his 3.9 fWAR tied him with Jung-ho Kang, who placed third in NL Rookie of the Year voting, for fourth among all rookies last season. Of course, playing for last year's hapless Phillies didn't help his exposure, but if you look over the past ten years, Herrera's performance ties him for 19^th among position-player rookies. This is a pretty impressive debut for someone the Rangers exposed two offseasons ago, and a shrewd parting gift from Ruben Amaro Jr. to the team he once oversaw.

Herrera may also be under-exposed because he didn't stand out among rookies in one particular area. He didn't have the power of Kris Bryant or Joc Pederson. He's wasn't blazing fast like Billy Burns or Delino DeShields. He didn't have Francisco Lindor's batting average, or Addison Russell's defense, or even Miguel Sano's BABIP. But what Odubel Herrera did was excel at nearly everything.

Although he was new to center field, the 23-year-old's defense graded out well according to DRS (10) and UZR (9.9), he ran the bases pretty well – including 16 stolen bases – and his bat was above average (wRC+ 110). The last bit seemed easy enough to poke holes in, however, as his lofty batting average (.297) seemed improbably supported by a BABIP that nearly touched .400.

If you migrate away from rookie leaderboards and sort by center fielder production for most of these categories, you'll often see the same player either just above or just below Herrera: Christian Yelich. In an equivalent number of plate appearances, Yelich hit one fewer home run (7), stole the same number of bases, hit for almost the same average (.300), supported by the similarly lofty BABIP (.370). Yelich, as it was pointed out in the offseason, has shown remarkable, nearly robotic, consistency in his offensive output. Not only that, but despite their very different routes to the major leagues, they are almost exactly the same age, both born in December of 1991.

But if there was one area where the Herrera and Yelich differed, it was their ability to take a walk. While Yelich walked a respectable 9.0% of the time last season, Herrera was more of a Kevin Pillar in that regards, taking a free pass in just 5.4% of plate appearances. But in the early going of 2016, Herrera and Yelich sit close to the top of the walk rate leaderboard, taking free passes in roughly a fifth of their plate appearances so far in this still-young season.

While it seems unlikely that either player will finish the season with their current walk rate, both have passed the 60 plate appearance plateau that marks the stabilization rate for the stat, so while regression will almost certainly come, their performances are probably reflecting something more than just random chance. If for some reason, you were forced to choose, Yelich seems like the better bet to finish with more free passes. Not only because he took nearly twice as many walks as Herrera last season, but because Yelich has a one of the more discerning pair of eyes at the plate, swinging at just 24% of pitches outside the zone for his career. But this season, he's taken it to another level, swinging at just 15% of such pitches, all while maintaining his swing rate at pitches inside the zone. Herrera, on the other hand, has reduced his outside-the-zone swing rate down to Yelich's career values this season, twelve percentage points down from his mark last season.

But while Yelich has the edge at maintaining the walk rate moving forward, Herrera's homer run power seems more likely to develop. In this regard, Yelich's greatest asset, his consistency, will also be what holds him back, as his consistent offensive output stems from his incredibly consistent batted ball profile.

Yelich has bat control that would make a hitting coach blush, with a standard deviation of less than 2% on the rate of each of the batted ball types above over his four seasons and still only one infield fly ball to his name (what?!). The problem for projecting a Yelich power outbreak– if you want to call it a problem – is overcoming this batted ball profile. If he's going to continue hitting so few flyballs, he’ll need a lot of luck to ever reach the homerun potential that many have been waiting for. But his extreme groundball rate brings with it the upside of an above-average but sustainable BABIP. Herrera, on the other hand, has hit nearly twice as many balls in the air as Yelich and may have been a bit unlucky with the homeruns, posting a below league average 8% HR/FB rate last season, compared to a slightly above-average 13% for Yelich.

If you had to wager anything of substance which player will be better over the coming seasons (which, come on, this is baseball, you really shouldn't if you value your money) Christian Yelich is the safer bet. While he’s increased his value by drawing more walks, it seems he'll continue to be more of a dubels hitter (had to sneak that in) if he’s not going to hit the ball in the air more often. Herrera, on the other hand, may be the player that we thought that Yelich could be, a perennial 20-20 threat with a plus-glove patrolling center field. And the Phillies got him for nothing. Well done, Ruben. Maybe your nickname will be updated posthumously (job-wise) to Saved Tomorrow Jr.

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Matt Jackson is a featured writer for Beyond the Box Score and a staff writer for Royals Review. You can follow him on Twitter at @jacksontaigu.