The Arizona Diamondbacks don't know what they have in recently promoted outfielder Adam Eaton. No one knows what they have, and that likely includes Eaton himself. But they do have about three weeks to figure it out.
What they don't have is a .355 hitter, which is Eaton's career mark in the minor leagues. It's hard to believe that his Trout-ian minor league numbers will translate the same way they did in Anaheim, but that doesn't mean Eaton isn't a good hitter. He was aided by some astronomical BABIP numbers, including a .432 mark in Triple-A this season, but the regression that Eaton should experience won't be as bad as it would be for many, as his line drive/ground ball approach, solid speed and low strikeout numbers all allow for a higher natural BABIP than most.
What they do have is, at the very least, an outfielder who is somewhere between a starter and a fourth-outfielder. He's a good outfielder that can handle center field in the spacious Chase Field outfield, and there is no reason to think that his line-drive approach won't make him a usable hitter against right-handed pitchers.
What they don't have is a middle-of-the-order hitter, as his career .510 slugging percentage and .966 OPS in the minors might indicate. Like the rest of his numbers, his slugging percentage is inflated by his high batting averages. He's not Juan Pierre though, and his doubles numbers and potential double-digit home run power is enough fo keep pitchers from knocking the bat out of his 5'9" frame.
What they do have is an opportunity. Eaton needs to play every day in September, against lefties and righties, so the Diamondbacks can begin to get a feel for how his game will translate to the major leagues.
Eaton has nothing left to prove in the minor leagues, but everything still to prove within the game of baseball. His pedigree and stature won't get him one at-bat he hasn't gone out and earned, but even in the crowded Diamondbacks outfield, Eaton needs to have his chance.
While Eaton isn't the Diamondbacks most talented outfielder (Justin Upton) and won't be their most productive offensive player (Jason Kubel, this year), but he does fill a major hole in their lineup - potential leadoff hitter.
The Diamondbacks have rotated primarily Willie Bloomquist and Gerardo Parra in the leadoff spot, with Chris Young getting 16 starts in the top spot as well. Parra, who is currently the team's fourth outfielder after winning a gold glove last season, sports the highest on-base percentage of the trio at .327.
It still remains to be seen if Eaton will be an every day player, but if he is, he will undoubtedly improve upon that number. Eaton has posted walk rates no lower than 9.4% at any level, and has done so despite instilling zero fear into pitchers from a power standpoint. The Pacific Coast League 2012 MVP was a hitter pitchers needed to take seriously, but at no point has a pitcher had to fear pounding the zone against Eaton in fear of him hitting a home run. This means that he earns his walks the old-fashioned way - by working the count and having a good eye at the plate - skills that tend to translate well in the majors.
In order to work Eaton into their lineup in 2013, the Diamondbacks will have to move an outfielder (or two). Kubel probably isn't going anywhere, but Upton, Young and Parra are all movable pieces. Which of that trio they should move is absolutely dependent on the offers they might get in return, with it likely taking a massive offer to trade Upton.
Despite his poor average, Young is still a valuable player, worth about 2 1/2 wins this season with a month left, and posting back-to-back 4.6 win-seasons (according to FanGraphs WAR) in 2010-11. Most of Young's value is due to his stellar defense in center field, and while Eaton can handle center, he will be a step down in that regard.
Assuming Eaton to be a 4 1/2 win player ever, let alone next season, is a tall task, but if he can be a three win player that's a better fit for the Diamondbacks needs, I'd argue that they'd be better off as a team.
Let's say that the team moves Young this off-season. That leaves the team with an Aaron Hill-Kubel-Upton-Montero-Goldschmidt 2-6 middle of the order. That's five players in the middle of the order, all of whom should post an OPS over .800 (assuming a healthy Upton), forming a potentially potent lineup without a catalyst at the top. It's like putting cheap gas in your Bentley.
Enter Eaton. Rather than having to put a player like Bloomquist in front of that power because Young needs to bat down in the order (or vice versa), Eaton allows everyone else to slide to the proper spot in the lineup. Even if he hits .270, it should come with a .340-.350 on-base percentage, meaning an additional 20-30 instances throughout the season when those guys come up with a baserunner on when they haven't this season.
The difference between Eaton becoming an everyday player will rest on two parts of his game - whether or not he can be an above-average defensive centerfielder in the major leagues, and how he handles left-handed pitching. If he is only adequate in centerfield and needs to be slid over to a corner, his offensive numbers will have to be that much more reminiscent of what he's done in the minor leagues. Ultimately, he'll have to reach his best-case scenario offensively if he's going to be a corner outfielder.
Against lefties, some platoon-spit is to be expected, but Diamondbacks will have to make sure Eaton isn't an automatic out against same-handed pitching. In the minors, Eaton does have a split, posting an OPS over 150 points lower against lefties. Thanks to his numbers, however, that OPS was still .823 against southpaws, with similar walks and strikeout numbers. The big dropoff was in power.
As long as he can still get on base against left-handers, then he'll be fine and can play every day, and if he can do it while manning centerfield, he can easily be a three win player. If that's the case, I'd much rather have a three win Eaton getting on-base in front of the Diamondbacks sluggers than a 3-4 win Young who has to be hidden in seven-hole.
The Diamondbacks have the unenviable task of trying to figure this out in a short period of time. The small sample size they will have on Eaton facing major league pitching doesn't give them much to work with, which means it won't be shocking when they send Eaton back to Triple-A where he will continue to dominate while continuing to put poor hitters in the leadoff spot. But at some point, Eaton will have to get his chance, and hopefully he will show enough this September to earn that chance in the Diamondbacks' eyes for the start of next season.