This is one of the most challenging lists we've worked on this offseason. There's so much talent here and it's extremely difficult to differentiate right now. An argument can be made for ranking any of the guys who are No. 1-4 here atop the list. And the same goes for the ordering No. 5-9. While these players will eventually have varying success in the big leagues, one thing's for certain: There are more than a few future stars listed below.
Notes: The level that appears following each player's name is the highest level where the player has registered over 100 plate appearances. We used an age cutoff of April 1st, 2008.
1. Justin Upton, ARI (8/25/87) - MLB
Upton went from South Bend to Visalia to Mobile to Arizona all prior to his 20th birthday. Sounds exhausting, but it's a very good sign. Selected No. 1 overall in the 2005 Draft, Upton reached the big leagues in 34 fewer at-bats than his older brother, B.J., who ranks third on this list. The younger Upton had a bit of a bumpy transition to pro ball during his first full season, leaving plenty of uncertainty for his second. He responded with a .294/.379/.502 vital line in 615 plate appearances over three stops last season. Upton played center field in the minors, but sharing the same outfield with No. 5 Chris Young, he'll be used in right by the Diamondbacks for now. He has 30 home-run, 1.000 OPS potential.
2. Jay Bruce, CIN (4/3/87) - AAA
When Upton graduated to the majors, Bruce became the darling of the minors. The 6-foot-3, 205-pound lefty has a line-drive stoke that allows him to generate power to all fields. It's possible that Bruce could amass more home runs per season than Upton. There are, however, a few things that Upton has on Bruce. For one, Upton doesn't swing and miss as often; secondly, he draws more walks. It's very challenging to separate these two right now because they've both been promoted so aggressively. We're putting a fair amount of trust in Upton continuing to grow in the majors. Bruce has outproduced him to date and could continue to do so.
3. Colby Rasmus, STL (8/11/86) - AA
There are quite a few people who like Colby Rasmus more than Jay Bruce. And those people aren't some kind of lunatic fringe. Rasmus endured a severe sinus infection last June. This wasn't some minor illness that Rasmus supporters are trying to milk for all it's worth. The guy lost about 10 pounds because of it -- said he'd never been that sick. Anyone who doesn't account for this in their evaluation of Rasmus isn't doing his or her homework. Rasmus had a .353/.700 batting average/slugging between May and August versus .203/.368 during June and July. The affect of his illness pretty black and white. The lefty hit .274/.380/.550 in Double-A last season (12.6% BB). He'll have to hit above the magical .300 line before some people officially see him as a potential stud. Do yourself a favor and toss that kind of logic aside. Rasmus could blossom into a 35+ home run talent and the best center fielder in the National League inside of the next three seasons.
4. B.J. Upton, TB (8/21/84) - MLB
It's probably difficult for most fantasy owners to digest seeing B.J. Upton below three "unproven" players on this list. He's coming off a very successful full pro season (.300/.385/.508) and his best years are still likely ahead of him. Don't take this ranking as a hack on the older Upton. He's probably one of the top three center fielders in the American League. But Upton isn't invincible. He struck out a lot last season (27.9%) and he cooled down in the second half of 2007 (.941 OPS vs. .861). B.J. Upton should have a better 2008 than his younger brother, Bruce, and Rasmus. As far as 2009 goes, the four could be in the same class. And by ranking B.J. below the other three, we're predicting that they'll pass him up by 2010.
5. Chris Young, ARI (9/5/83) - MLB
Another guy who fantasy owners may not expect to see this low, Young is coming off an undeniably impressive rookie season. And though he did hit 32 home runs and show some speed, his .236/.293/.466 vital line is far from flawless. Young is an extreme pull-hitter who gets the ball in the air but doesn't hit a ton of line drives. He's still youthful enough to make significant strides as a hitter and given his success over the last three years, we're confident that he'll improve in 2008.
6. Hunter Pence, HOU (4/13/83) - MLB
Remember back when Pence was knocked for having a funky swing? The big righty had a monster rookie season (.322/.360/.539) and shook a lot of doubters -- production can do that. Pence is now playing right field with Michael Bourn taking over in center, but he still has the speed to play center if needed. A good line-drive hitter, Pence could hit 25+ home runs this season. And if he can get his big league walk rate (5.5% last season) close to what it was in the minors over the last three seasons (9.9%), he could become a Chase Utley-type player on offense.
7. Cameron Maybin, FLA (4/4/87) - AA
We'll print it again because we're not sure if it has been seen enough: .276/.367/.618 with 7 HR. That's Maybin's line from last August -- A+/AA/MLB (89 PA). His line-drive rate (appx. 11.2% in '07) has been questioned regularly over the last year in our forums -- he was a good line-drive hitter in August, though. His strikeout rate (25.5% in '07) is also a legitimate source for concern. Maybin's career could head in so many directions. He could be a star, he could be a below-average big leaguer. If things begin to click for him this year, he could shoot up this list.
8. Lastings Milledge, WAS (4/5/85) - MLB
Milledge was shipped to the Nationals for Ryan Chruch and Brian Schneider over the offseason -- the trade sent shock waves across the Internet; it could wind up looking almost as bad as Scott Kazmir for Victor Zambrano. A career .305/.385/.479 minor leaguer, he reached the big leagues at the tender age of 21. He has compiled 323 MLB at-bats since then and hit .257/.326/.414. Milledge was awarded a 2008 starting job by the Nationals. And this year could be his breakout party. The 2003 first rounder (12th overall) is an excellent line-drive hitter with potential to top 25 home runs a season. It's likely that he'll become an above-average MLB regular.
9. Adam Jones, BAL (8/1/85) - MLB
A case could be made for ranking Jones ahead of Milledge. Selected 25 picks after Milledge in the 2003 Draft, Jones is a career .291/.354/.476 minor leaguer. He may have more power than Milledge but he likely won't reach base as frequently and he'll strike out more. Like Milledge, Jones was also traded this offseason -- the centerpiece of a deal that brought Erik Bedard to Seattle. We'll be surprised if he outproduces Milledge in 2008 but they could have similar overall values in 2009. Jones is just a bit more of a wild card because he has yet to prove himself in the big leagues.
10. Felix Pie, CHC (2/8/85) - MLB
Similar to Jones, Pie struggled with Triple-A his first time around but found immense success in his second trip through the level. Also similar, he has yet to live up to his potential in the big leagues. The lefty is a career .300/.358/.468 minor leaguer -- very similar to Jones. And while Pie may not strike out as often as Jones, he doesn't have nearly as much opposite-field power as the Orioles' center fielder. Pie could easily develop into an above-average big leaguer. He has a good arm and could top 20 home runs a season some day.
Honorable Mentions: Fernando Martinez (NYM), Jacoby Ellsbury (BOS), and Andrew McCutchen (PIT).
Adam Foster can be reached at adamf@projectprospect.com.