As always, players must meet MLB rookie eligibility requirements (under 130 at-bats or 50 innings pitched at the major league level) to qualify as part of an organization's farm system.
20. Minnesota Twins
Top Prospect: Miguel Sano, third baseman
The Twins system is deep in the low minors, but lacks impact players in any levels above High-A. Sano is the cream of the crop; he boasts some of the best pure power in the minors and could be a perennial All-Star if he doesn't outgrow the hot corner.
Outfielder Joe Benson and starters Kyle Gibson and Liam Hendricks could all contribute in 2012, but none possesses star power. Oswaldo Arcia and Eddie Rosario are outfielders with more potential, but neither is close, and former organization golden boy Aaron Hicks never translated his tools into numbers. Shortstop Levi Michael and starter Alex Wimmers are more recent first-rounders with more probability than upside.
19. Los Angeles Angels
Top Prospect: Mike Trout, outfielder
Trout deserves serious consideration -– even over Bryce Harper -– for best overall prospect in the game. He'll likely be an All-Star the first time he gets over 500 at-bats.
The Angels have a nice mix of infield prospects in third baseman Kaleb Cowart, shortstop Jean Segura, first baseman C.J. Cron and second baseman Taylor Lindsey, but none has played above High-A. Garrett Richards is likely ready to compete for the Angels' fifth starter spot now, and has a ceiling as a third starter. Starter Trevor Reckling regressed badly in 2011, but Johnny Hellweg had a breakthrough campaign.
18. New York Mets
Top Prospect: Zack Wheeler, starting pitcher
The Mets' robbing of the Giants in acquiring Wheeler for Carlos Beltran last season was downright criminal, and pairing him with Matt Harvey gives the Mets one of the best one-two starting pitcher punches in the minors.
Righty Jeurys Familia has upside as well, but may end up in the bullpen. The Mets would do well to avoid hampering his development the way they did with Jenrry Mejia. Brandon Nimmo, a 2011 first-rounder, is an exciting prospect, but is at least three seasons away. Wilmer Flores and Reese Havens are the keys for this system –- it's not hard to envision either as an All-Star or out of baseball by 2015.
17. Houston Astros
Top Prospect: Jonathan Singleton, first baseman
The Astros have done a good job turning their farm system around in short order, and while it's not elite, it's certainly now respectable. Singleton and righty flame thrower Jared Cosart were a terrific return for Hunter Pence. Along with 2011 first-round outfielder George Springer, they're clearly the three best prospects in the system.
Shortstop Jonathan Villar and outfielder Domingo Santana are two other solid prospects who used to be in the Phillies organization. Starters Brett Oberholtzer and Mike Foltynewicz are more useful to know for Scrabble purposes than baseball ones, but can become No. 4 starters.
16. Chicago Cubs
Top Prospect: Anthony Rizzo, first baseman
Theo Epstein and Co. inherit a system deep with position players, but somewhat barren on the pitching end. Rizzo and center fielder Brett Jackson are both MLB-ready, and they should be batting near the middle of the Cubs' lineup by midseason.
Catcher Wellington Castillo and outfielder Matt Szczur look like second division starters or excellent backups, and 2011 first-rounder Javier Baez is a prototypical mashing third baseman. Right-handers Dillon Maples, Trey McNutt and Chris Carpenter all throw hard, but might end up in the bullpen. Josh Vitters and Dan Vogelbach are deeply flawed players, but both can hit.
15. Colorado Rockies
Top Prospect: Nolan Arenado, third baseman
Despite the failures of first-round lefties Tyler Matzek and Christian Friedrich, the Rockies have been able to quietly add talent to their system in the past several months. Arenado is the best third base prospect in the minors and could be MLB-ready by mid-2012.
Drew Pomeranz was a great get for Ubaldo Jimenez, and has No. 2 starter stuff even at Coors Field. Chad Bettis, Trevor Story and Tyler Anderson make for a nice group of players in the low minors, while catcher Wilin Rosario and outfielders Tim Wheeler and Charlie Blackmon will all likely contribute in the majors this year.
14. Pittsburgh Pirates
Top Prospect: Gerrit Cole, starting pitcher
The Pirates took Cole with the first overall pick in this year's draft, and continue to add to a farm system littered with high-upside players. Cole joins Jameson Taillon and Luis Heredia to form a ridiculously strong crop of right-handed pitchers who likely won't make an impact until mid-2013 at the earliest.
Josh Bell and Starling Marte form an intriguing pair of multi-tool outfielders, and Robbie Grossman could figure into the outfield future in Pittsburgh as well. Kyle McPherson and Jeff Locke should make appearances as back-end starters this season, and catcher Tony Sanchez and pitcher Stetson Allie still have time to turn their careers around. This system is one solid trade or draft away from approaching the Top 10.
13. Boston Red Sox
Top Prospect: Will Middlebrooks, third baseman
The Red Sox' farm system lacks any blue-chip prospects, but is incredibly deep. Middlebrooks and Jose Iglesias will likely form the team's left side of the infield in short order, with Xander Bogaerts, Garin Cecchini and Sean Coyle contributing down the line. Anthony Ranaudo now looks like a mid-rotation starter, but UConn product Matt Barnes has ace upside.
Ryan Lavarnway and Alex Wilson should contribute to the majors this year, while Bryce Brentz and Brandon Jacobs are two power-hitting outfielders for the future. The Sox' 2011 draft haul of Barnes, Blake Swihart, Jackie Bradley Jr. and Henry Owens should go a long way toward replenishing a system depleted by trades.
12. Washington Nationals
Top Prospect: Bryce Harper, outfielder
The Nationals began the offseason with a borderline top five system, but were drained in the Gio Gonzalez deal. They still have baseball's best prospect in Harper, and added arguably the best hitter in the 2011 draft in second/third baseman Anthony Rendon. They added more upside in the draft through pitchers Alex Meyer and Matt Purke, and took five-tool outfielder Brian Goodwin as well. Robbie Ray and Sammy Solis could be mid-rotation lefties in a few years, and Steve Lombardozzi could impact the 2012 club. This is no longer an elite system, but it's still very good.
11. St. Louis Cardinals
Top Prospect: Shelby Miller, starting pitcher
The Cardinals have drafted well and been active in the international market in recent years, and their farm system is now reaping the rewards. Miller is close to MLB ready and projects to be an ace, and starter Carlos Martinez and outfielder Oscar Taveras are two insanely talented Dominican signees.
Zack Cox and Kolten Wong don't awe scouts, but both should at least be average MLB regulars by mid-2013. Add in high-upside starter Tyrell Jenkins, plus 2011 contributors Lance Lynn and Eduardo Sanchez, and this is a very well balanced system.
View all of the MLB farm system rankings: 30-21 I 20-11
Check back on NESN.com on Monday for farm system rankings 1-10.
Will Middlebrooks photo (left) via Flickr/murphman61
Mike Trout photo (right) via Flickr/Keith Allison
