While the American League Rookie of the Year award has already been decided, the Senior Circuit is home to a little more drama. As the pennant races wind down, several players (mostly from the NL Central) are making a compelling case for the Rookie of the Year award. And although there may not be one definite candidate from the NL, there are plenty of players with at least some claim to the award.
For your reading purposes, I'd like to posit four leading contenders from both the pitching and hitting sides of things, as well as two emergent players who probably don't have the playing time to really be in contention for the award.
Five Important NL Rookie Hitters
Perhaps some of you have heard of Bryce Harper? Before Mike Trout happened to the league this year, there was some discussion that Harper was the best prospect in the minors. He was supposed to be this unbelievable phenom, blah blah blah. While the saber-sphere has adopted Trout as the Next Big Thing, Harper has, rather quietly, established himself as a phenomenal young talent. In any other year, people would be raving about a four- WAR 19-year-old with plenty of room to improve and unreal power. He's also an All-Star, which is kind of awesome.
Though Harper doesn't have the same offensive chops (yet) as competitors Norichika Aoki and Todd Frazier have shown this season, he's posted very strong fielding numbers in both center and right field. He's no Trout with the Glove, but his arm has led him to hold more than a few runners and notch seven assists and three baserunner kills. He's already a fine all-around player, with time to grow into his prodigious power and learn how to handle left-handed pitching.
Norichika Aoki is much more of a finished product, and the Japanese import has been a pleasant surprise for the Brewers on the season. Aoki has been an on-base machine for the Brew Crew, racking up doubles and stolen bases with abandon. And his batting average is actually a little low, given a BABIP of only .308 on the season. But while Aoki has been a pleasant surprise and an above-average contributor, he's about 11 years older than Harper, and doesn't have the defensive chops that the young National has, according to most metrics. He's been out-of-place playing limited time in center field, and his glove profiles much better in right. Oh, and for a more comprehensive look at Aoki, and his value, check out this article by Julian Levine from last month.
There are two rookies in Cincinnati who've made a solid impact on the Reds' run to the NL Central title. Todd Frazier has proved an invaluable bat in the middle of the Cincy lineup, especially considering the team's loss of Joey Votto for several weeks. Frazier has provided 18 HR and a .341 OBP while splitting time at first, third and in the outfield. He's a classic slugger who doesn't acquit himself well at any position on the diamond, which makes him the virtual opposite of teammate Zack Cozart. Cozart has not hit particularly well on the season, as evidenced by his 82 wRC+ and sad, sad .285 OBP. But Cozart has done two things fairly well: when he hits, he can provide some power, as evidenced by his 15 HR (almost as many as Frazier!) -- and he's also managed to put up very solid defense at shortstop. The Ole Miss product has shown range and relative consistency in the middle of the diamond, and advanced metrics like UZR and DRS put him squarely in the group of good-to-great defensive shortstops.
As good as these two rookies have been for the Reds, the team perhaps had a chance to have another one who is even better, if not for the Mat Latos trade. Although Yasmani Grandal has only seen 185 plate appearances this season for the Padres, he's been dangerously effective in his limited action. Although his limited time in the bigs will prevent him from being a serious contender for Rookie of the Year, Grandal has posted a sterling 140 wRC+ in his small sample size, and looks to be the real deal with the bat. If he can keep up this potent combination of plate discipline (26 BB in 185 PA) and power (.185 ISO), the Padres could be looking at their own version of Buster Posey for the next few years.
Five Important NL Rookie Pitchers
Let's first give credit where it's due: all of the pitchers in the table above are better-than-league-average starting pitchers in their rookie seasons. That's pretty phenomenal stuff. But no rookie pitcher has been more phenomenal, at least over an extended period, than Diamondbacks starter Wade Miley. Deservingly an All-Star this season, Miley is the gold standard for rookie pitchers, having come through for 177 innings while posting an era 26% better than league average, and an FIP 22% better than league average as well. He's used great control (look at that walk rate) to offset a middling K/9 number, and in my opinion, well-deserves his position atop the rookie starting pitcher leaderboards.
Then there's Mike Fiers, who's blown through hitters to the tune of over a strikeout per inning, while only walking two-and-a-half batters per nine. While Miley has been the better performer over a longer stretch, if I had to pick a pitcher who's stats pointed to more long-term success, I'd go with Fiers. Though he hasn't logged nearly the same amount of ML innings, that solid walk rate, when paired with that impressive strikeout rate and slightly-better FIP, look like a harbinger for more future success. But, since we should base RoY voting on this year's performance, I'd think that Miley still holds a substantive edge, especially considering his IP number.
Lance Lynn was also an All-Star this season, and his strikeout rate is very close to Fiers's, while posting similar IP numbers to Miley. Unfortunately, his walk rate, ERA, and FIP all sit much closer to league-average than the other two. A two-to-three win starter is a seriously valuable asset, but Lynn just doesn't have the numbers that either Fiers or Miley have overall, though he does have 16 wins on the season. Lucas Harrell is basically a poor-man's Lance Lynn: a pleasant surprise during an awful year in Houston, and a solid potential back-of-the-rotation starter for a few years, but not really worthy of serious Rookie of the Year consideration given his competition.
With only 59.1 innings on the season, Matt Harvey isn't really worth considering as a real Rookie of the Year candidate. However, the hot new thing in Queens put up eye-popping strikeout numbers (and stuff) while keeping his ERA lower than 3.00 in limited action. 10.62 strikeouts per nine is a very impressive number for a reliever, let alone a rookie starter. In fact, Aaron Gleeman at HardballTalk posted an interesting statistic: only seven pitchers have struck out more than 10 per nine and made 10 or more starts at the age of 23. The names are guys like Strasburg, Santana, Koufax, and Prior ... as well as "Sudden" Sam McDowell, Bobby Witt, and Scott Kazmir. That's some wild company. He's still got a few control issues to work out, but unlike all but Fiers above him in my table, Harvey is the one starter who looks like he could be an ace somewhere down the line.
If I had to vote today for Rookie of the Year, my ballot would really just come down to three big choices: Harper, Miley, and Aoki. Fiers, though effective, doesn't have the same IP or games played as the players above him, and his WAR / rate stats aren't quite impressive enough to make up the difference. Aoki has been great, but the difference in defensive ability and age makes me slot Harper slightly ahead of the Brewers rookie. (Sound familiar?) That leaves two All-Stars in Wade Miley and Bryce Harper. Honestly, I don't think you could go wrong with either choice for 2012. Harper is the better story (phenom, age, hype), and plays for a franchise that has surged to the playoffs, while Miley is more impressive as compared to the league average at his position. Both players are very similar when it comes to WAR.
With all that in mind, I guess I'll go with Harper's age as my tie-breaker, as he's doing things during his age-19 season that other players just don't do. It's a tough break for Wade Miley, whose performance I see as more impressive than Craig Kimbrel's RoY-winning effort last season, or the 2008 and 2009 campaigns by Geovany Soto and Chris Coghlan as well. A compelling case can be made for either Wade Miley or Bryce Harper, which honestly isn't something I would have expected before the 2012 season started.