Adam Eaton's speed could make him a fixture atop Arizona's lineup for years to come. (Getty Images)
Earlier today, I examined the top impact rookies in the American League, not necessarily the top prospects overall or in a given organization, but the ones most likely to make significant contributions at the major league level in 2013. Now it's time to turn to the National League, where the slate appears to be dominated by pitching.
As noted before, I'm not a scout, and I've seen very few of the players on the top prospects lists myself. But when I want to know who's who and what's what in the world of minor leaguers on the rise, I turn to the lists and descriptions from the team at Baseball America, ESPN Insider's Keith Law, MLB.com's Jonathan Mayo, Baseball Prospectus' Jason Parks and SB Nation's John Sickels (the latter two lists are forthcoming next week) and attempt to distill those expert observers' reports and opinions into information I can use here. Not all of the players below may break camp with their respective major league teams; I've ranked them according to my own understanding of what they'll contribute in 2013.
RHP Shelby Miller, Cardinals. The Cardinals may have the top farm system in the game, and they're deep in starting pitching. With the recent news that Chis Carpenter will likely miss the season, the likelihood of the 22-year-old Miller making an impact has increased. A 2009 first-round pick out of a Texas high school, he has been on BA's list in each of the past four years, and in the top 15 for the past three. He came into last year at No. 8 but endured an uneven season at Triple-A Memphis, where he was hit hard (1.6 homers per nine, 4.74 ERA), though a late-season tweak in his mechanics helped bring those numbers down from loftier heights. He still struck out 10.5 per nine before a late-season promotion to the big club, where he whiffed 20 in 17 innings (including the playoffs), mostly out of the bullpen.
Miller has a mid-90s fastball that can touch 97, but it's a bit flat, making him vulnerable to the longball; his out pitch is a hard curve, and his changeup should become a third above-average offering, giving him top-of-the-rotation potential. Fellow rookie Trevor Rosenthal, a 22-year-old righty who sits 92-97 as a starter and has touched 100 out of the bullpen, could get a look if the team decides Miller should start the year in the minors.
RHP Wily Peralta, Brewers. The 23-year-old Peralta doesn't have the high ceiling of some of the other pitchers here — he's midrotation material, not a future ace — but he's got the clearest opportunity out of the gate, having more or less secured a rotation spot thanks to his 29 innings of 2.48 ERA ball with the Brewers last season. His numbers at Triple-A Nashville weren't stellar due to command woes (4.66 ERA and 4.8 walks per nine to offset 8.8 strikeouts per nine), but his stuff is still impressive: two- and four-seam fastballs that he can command to both sides of the plate at speeds in the mid-90s, as well as a slider and changeup that could be above-average with improved consistency. A wider separation in velocity between the fastballs and the rest of his arsenal would help.
CF Adam Eaton, Diamondbacks. Not to be confused with the former pitcher of the same name, Eaton is a 19th round 2010 pick out of Miami (Ohio) who put himself on the map by hitting .355/.456/.510 at four minor league spots over the past three years, including .381/.456/.539 at Triple-A Reno last year. He went on to hit .259/.382/.412 in 103 PA with the Diamondbacks, who traded Chris Young to the A's over the winter to open up centerfield for him. The 24-year-old lefty isn't exactly a blue-chipper; BA ranked him 73rd, the highest of any aformentioned lists, and both MLB and ESPN have him in the 90s. Eaton doesn't have a ton of power, but he does have plenty of speed (11 homers and 54 steals in 868 PA at Double-A and Triple-A) to complement good plate discipline, making him a likely top-of-the-order staple. His defense in center — particularly his reads — needs work, but the opportunity is there for him to secure the job in spring training, once again consigning Gerardo Parra to fourth outfielder status.
C Travis d'Arnaud, Mets. Acquired from the Blue Jays in the R.A. Dickey blockbuster trade, the 24-year-old d'Arnaud is a two-way catcher who ranked sixth on MLB's list, 14th on ESPN's list and 23rd on BA's list. He's coming off a year in which he batted .333/.380/.595 with 16 homers in 303 plate appearances at hitter-friendly Las Vegas, but a torn posterior cruciate ligament in his left knee ended his season in late June 25; though he didn't undergo surgery, he didn't play again. Indeed, injuries have become a recurring theme in his young career, as he has played more than 71 games in a season just twice, with back and thumb injuries cutting into his time as well.
At the plate, d'Arnaud is an above-average hitter for a catcher, with good contact and power potential. Behind it, he's a good receiver with a strong arm but an occasional tendency to rush his throws and lose accuracy; he threw out 30 percent of would-be base thieves in 2012. Because of the knee injury and service time issues, he's likely to start the year in the minors, but should be up sometime this summer, hopefully providing Mets fans some consolation for the loss of the popular knuckleballer in the form of a cornerstone player of their rebuilding effort.
LHP Tyler Skaggs, Diamondbacks. A 2009 supplemental first round pick who was acquired from the Angels in the Dan Haren trade the following summer, Skaggs was roughed up for a 5.83 EA in six late-season starts for Arizona. Nonetheless, the 21-year-old southpaw ranked 12th on both the BA and ESPN lists after a year in which he delivered a 2.87 ERA and 8.5 strikeouts per nine in 122 1/3 minor league innings split between Double-A Mobile and Triple-A Reno. Skaggs has three above average pitches with which he can miss bats: a 91-93 mph fastball, a big two-plane curveball, and a deceptive changeup; if his command improves, he's a future No. 2 starter. As it is, he'll have to battle sophomore Patrick Corbin for the last spot in the Diamondbacks' rotation, and could face an additional challenge once Dan Hudson returns from Tommy John surgery in midsummer. Still, he's impressed talent evaluators with his ability to evolve as he's climbed the ladder, and if he continues to do so, he'll have nothing to worry about.
RHP Gerrit Cole, Pirates. The top overall pick of the 2011 draft, Cole put up solid numbers across three levels in his first pro season (2.80 ERA and 9.3 strikeouts per nine in 132 innings). With a classic power pitcher build (6-foot-4, 220 pounds), the 22-year-old righty figures to be even better than that thanks to a high-90s fastball — the only fastball of any pitcher on BA's list that was graded an 80, the highest possible mark — as well as an outstanding slider and a plus changeup, positioning him as a true ace in the making. With just 59 innings of Double-A and six at Triple-A, he could use some upper-level experience to refine his offerings and his mental approach; as Law wrote, "He has to break that tendency to try to respond to adversity on the mound by putting the next pitch through the catcher, working instead on locating it and mixing in those other pitches." There's little standing in his way in the Pirates' current rotation, and Cole may be a big piece of the puzzle in their finally breaking their epic sub-.500 streak -- 20 years and counting -- so he should be up sometime this summer.