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Also in this series: 6-10, 11-15, 16-20, 21-25, 26-30, 31-35, 36-40.

5. Alex Meyer | Starter | DOB: 1/90 | Throws: Right | Trade: Nationals

YEAR     LV      G     GS      ERA        IP       H     HR      SO     BB
2012     A-     18     18     3.10      90.0      68      4     107     34
         A+      7      7     2.31      39.0      29      2      32     11

Alex Meyer split his pro debut between two levels of Single-A, posting a 2.86 ERA and .211 opponents' batting average with a 139-to-45 strikeout-to-walk ratio in 129 innings. And then 17 months after giving Meyer a $2 million signing bonus as the 23rd pick in the 2011 draft--seven spots ahead of where the Twins took infielder Levi Michael--the Nationals sent the 6-foot-9 right-hander to Minnesota in exchange for Denard Span.

Meyer regularly works in the mid-90s, topping out close to triple-digits, and Baseball America's season review of the South Atlantic League praised his "wipeout slider in the mid-80s" and noted that his changeup "could become an average third pitch." Keith Law of ESPN.com described Meyer as a "potential frontline starter," writing that "his slider is filthy, a bona fide out pitch" and "his changeup has improved to the point where it's probably a future-average pitch."

His control was very shaky at the University of Kentucky, but Meyer's walk rate was a respectable 3.1 per nine innings in his pro debut and he also induced 52 percent ground balls. Expectations should be held in check considering Meyer hasn't even thrown a pitch above Single-A yet, but he immediately becomes the Twins' top pitching prospect and is arguably the organization's best, highest-upside pitching prospect since Matt Garza in 2006.

4. Aaron Hicks | Center Field | DOB: 10/89 | Bats: Switch | Draft: 2008-1

YEAR     LV      PA      AVG      OBP      SLG     HR    XBH     BB     SO
2010     A-     518     .279     .401     .428      8     41     88    112
2011     A+     528     .242     .354     .368      5     41     78    110
2012     AA     563     .286     .384     .460     13     45     79    116

Last year at this time Aaron Hicks' stock had gradually slipped due to questions about his low batting averages, modest power, perceived passiveness at the plate, and lopsided splits as a switch-hitter. He answered all those questions and then some at Double-A, batting .286 with 13 homers, 45 total extra-base hits, 32 steals, and 79 walks in 129 games while posting an .828 OPS from the left side and an .881 OPS from the right side.

His season was so encouraging that the Twins surprisingly traded both Denard Span and his assumed center field replacement Ben Revere, suggesting they believe Hicks will be ready for the majors in 2013. Whether that's Opening Day or midseason or September remains to be seen, but the former first-round pick has the range and arm strength to be a defensive asset right now, at age 23, and made major strides offensively in New Britain.

His defense has always gotten very positive reviews, as Hicks combines plus range with an arm that had some teams liking him more as a pitcher coming out of high school. He strikes out quite a bit and may never hit for great batting averages, but Hicks has drawn a ton of walks at every level and has the speed to take advantage of his on-base skills. If last year's power development sticks he has a chance to be a star and if not he should be a solid regular for a long time.

3. Oswaldo Arcia | Right Field | DOB: 5/91 | Bats: Left | Sign: Venezuela

YEAR     LV      PA      AVG      OBP      SLG     HR    XBH     BB     SO
2010     RK+    283     .375     .424     .672     14     42     19     67
2011     A-      81     .352     .420     .704      5     14      9     16
         A+     227     .263     .300     .460      8     24      9     53
2012     A+     235     .309     .376     .517      7     26     23     45
         AA     299     .328     .398     .557     10     35     28     62

Generally speaking few organizations promote prospects slower than the Twins, but every once in a while they veer from that approach with a special player and that's how Oswaldo Arcia reached Double-A a month after his 21st birthday last season. Arcia has produced at every level since the Twins signed him out of Venezuela as a 16-year-old in 2007, hitting .314/.371/.535 in 374 career games despite constantly facing older, more experienced competition.

For much of that time he put up big numbers despite ugly strikeout-to-walk ratios, but that's not uncommon amid aggressive promotions and last season Arcia walked more and struck out less to cement his status as an elite hitting prospect. He batted .328/.398/.557 in 69 games at Double-A, becoming the first prospect to top a .950 OPS in the Eastern League at 21 or younger since David Wright in 2004. Wright is now 30 years old and a six-time All-Star.

Arcia still has some work to do in terms of making consistent contact and handling left-handed pitching, but everything else about his performance and age relative to the levels of competition suggest he'll develop into a middle-of-the-order bat. And while he had to shift to right field after starting out as a center fielder he should add some value defensively too, with solid range and a strong arm.

2. Byron Buxton | Center Field | DOB: 12/93 | Bats: Right | Draft: 2012-1

YEAR     LV      PA      AVG      OBP      SLG     HR    XBH     BB     SO
2012     RK-    102     .216     .324     .466      4     11     11     26
         RK+     87     .286     .368     .429      1      8      8     15

Given their choice of college starting pitchers with the No. 2 pick in June's draft the Twins went for long-term upside over short-term need, taking Georgia high school center fielder Byron Buxton. He hit over .500 as a senior and struck out 18 batters in a seven-inning complete game to win the state championship as a pitcher, with Baseball America, ESPN, and MLB.com all ranking Buxton as the best player in what was considered a weak overall draft class.

Buxton signed quickly for a $6 million bonus that's the highest in franchise history and played in two levels of rookie-ball for his debut, totaling 19 extra-base hits, 19 walks, and 11 steals in 48 games at age 18. He also struck out 41 times and hit .248, but the power, patience, and speed were all very encouraging considering the pre-draft questions about the low level of competition he faced in high school and the fact that he was picked mostly for his physical tools.

He'd be the clear No. 1 prospect for many and perhaps even most teams, but my rankings tend to be somewhat conservative with players who've yet to face full-season competition and ... well, the guy in the Twins' top spot is pretty good. Buxton has immense upside as a potential five-tool center fielder, the early returns are positive, and the Twins were right to pass on non-elite college arms for him, but he's still a very long way from the big leagues and very far from a sure thing.

1. Miguel Sano | Third Base | DOB: 5/93 | Bats: Right | Sign: Dominican

YEAR     LV      PA      AVG      OBP      SLG     HR    XBH     BB     SO
2010     DSL     80     .344     .463     .547      3      6     14     17
         RK-    161     .291     .338     .466      4     18     10     43
2011     RK+    293     .292     .352     .637     20     45     23     77
2012     A-     553     .258     .373     .521     28     60     80    144

After crushing rookie-ball pitching to establish himself as an elite prospect Miguel Sano moved up to full-season competition at low Single-A and had the second-highest OPS in the Midwest League. He got off to a huge start, slumped for a couple months, and then finished strong while the Twins opted against a second-half promotion to high Single-A. His high strikeout total and low batting average were disappointing, but Sano had 80 walks and a league-leading 28 homers at age 19.

To put that production at Sano's age in context, consider that since 2000 only seven hitters have topped his .893 OPS as teenagers in the Midwest League, including Mike Trout, Prince Fielder, and current stud prospects Wil Myers and Oscar Taveras. That doesn't guarantee stardom, but it shows just how rare it is for a 19-year-old to be among the best hitters in a full-season league and why there's no reason to fret about a .258 batting average or lack of consistent contact yet.

There is reason to wonder about Sano's long-term home defensively, as reviews of his range and glove at third base are mixed at best and given his size a move to right field or first base looms as a strong possibility. For now the Twins will give him more time at third base in the hopes that his arm strength and athleticism can carry him, but ultimately Sano's ceiling is so offense-driven that sliding down the defensive spectrum won't change much. He's the real deal.

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