I voted in the NL, so let's start there. It was the first time I had the opportunity to vote for the rookie of the year since joining the Baseball Writers' Association of America a few years ago, and it's an award I enjoy discussing more than the others because it connects to the part of my job that revolves around scouting and evaluating prospects. This year's NL crop was a deep one but had just one true breakout prospect, so he was at the top of the ballot I filed the day after the season ended.
Filling out this ballot turned out to be easier than I had expected it to be when September began, thanks to a .330/.400/.643 (BA/OBP/SLG) month from Harper that saw him pull away from Aoki and Todd Frazier and edge ahead of Miley for the top spot on my ballot. Harper ended the season at 4.9 wins above replacement (FanGraphs' version), with roughly four wins coming from his bat and about two-thirds of a win coming from the defensive value of his arm alone, enough to put him in a virtual tie with Miley at 4.8 WAR (FanGraphs) for tops among NL rookies.
I put Harper over Miley, even with my reluctance to rely too much on the precision of advanced defensive metrics, for a variety of reasons that come down to the essence of the award itself. The purpose of this award has to be to highlight a rising star in the game, and to help further the image and the marketing of the sport by pointing out to all fans, "Hey, watch this guy, because he's going to be great for a long time." Harper performed at an extremely high level this year, posting one of the best seasons by a teenager in baseball history, and has the greatest potential of any NL rookie in this class to end up an MVP-caliber player. Those factors elevated him over Miley, who had a solid season he might repeat many times but who is five years Harper's senior and who isn't likely to become a Cy Young contender at his peak.
Whether you rely on FanGraphs or Baseball-Reference for WAR figures, Harper's total ranks as the best by any teenage position player ever. The next four, per Baseball-Reference, are Mel Ott, Edgar Renteria, Ken Griffey Jr. and Ty Cobb -- two Hall of Famers and one future member in the set. The only teenagers to post higher slugging percentages in a season (minimum 300 plate appearances) than Harper's .477 were Ott and Tony Conigliaro. The only teenagers to post higher OBPs were Ott, Renteria, Cobb, Conigliaro, Mickey Mantle and former Washington Senator Buddy Lewis, who might be better known today had he not spent his time from age 25 to 27 flying for the U.S. Air Force in World War II. Harper is in some pretty elite company already, and he just turned 20 a few weeks ago. Had Miley blown him away in straight performance, I would have reversed the names, but they were roughly equal on the field, and the context gives a large edge to Harper.
The last spot came down to Aoki and Frazier, with Aoki winning almost by default when Dusty Baker made Frazier a part-time player, a role in which Frazier struggled although the two issues might not be connected. Aoki played more and contributed more value on defense, something that will always be an issue for Frazier, whose best position is probably left field but whose OBP will be a problem at one of the diamond's highest-offense spots. Neither player was that young in 2012, nor does either player project to be a star. I easily could have put Frazier in Aoki's spot, choosing to give it to the slightly more well-rounded player who also garnered more playing time. Mike Fiers was the only other name in the mix and would have been fifth if the ballot had more spots, although the more the league saw him, the worse he pitched.
No other player merited serious consideration for the top three spots. Anthony Rizzo could have made this interesting had he spent all season in the majors, but in 87 games, he couldn't come close to Aoki's or Frazier's production, let alone Harper's. Wilin Rosario's 28 homers from behind the plate might get him some attention, but he is a brutal receiver and did nearly all his offensive damage at Coors Field. Lance Lynn shows up on some leaderboards as a rookie but lost his eligibility in 2011 due to the number of days he spent on the 25-man roster.
The AL rookie of the year ballot is pretty anticlimactic. Trout was the most valuable player in the AL this season, and there wasn't another rookie, position player or pitcher, who came close. I've got Yu Darvish in the second spot; he finished fourth among all AL pitchers in FanGraphs' WAR and fifth in strikeouts despite making just 29 starts. He also made significant adjustments over the course of the summer, throwing more strikes and relying more heavily on his cutter, giving me greater optimism as he heads into his second MLB season. I've got Jarrod Parker third over teammate Yoenis Cespedes. Parker was more valuable overall, in large part because he played closer to a full season, while Cespedes was a below-average defender in center, negating some of the value of his power output.