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Also in this series: 1-5, 6-10, 16-20, 21-25, 26-30, 31-35, 36-40.

15. Brandon Peterson | Reliever | DOB: 9/91 | Throws: Right | Draft: 2013-13

YEAR     LV      G     GS      ERA        IP       H     HR      SO     BB
2013     RK+    19      0     2.96      27.1      22      3      40      9
2014     A-      9      0     0.71      12.2       9      0      19      2
         A+     31      1     1.80      45.0      28      0      65     17
2015     A+     21      0     0.85      31.2      14      0      44     15
         AA     20      0     3.38      29.1      30      1      33     13

He's largely flown under the radar in a Twins farm system filled with several high-profile reliever prospects, but none have performed better than right-hander Brandon Peterson since his pro debut in 2013. Drafted in the 13th round out of Wichita State, the Minnesota native dominated rookie-ball in 2013, overpowered hitters at two levels of Single-A in 2014, and kept cruising to Double-A last season at age 23.

Overall he's got a 2.04 ERA in three pro seasons, racking up an incredible 201 strikeouts in 146 innings. In his two full seasons above rookie-ball Peterson has held opponents to a .191 batting average and one home run in 479 plate appearances, striking out more than one-third of the batters he faced. Peterson was also no slouch at Wichita State, posting a 1.13 ERA and 42/15 K/BB ratio with zero homers in 40 innings.

His raw stuff can't match those numbers because short of maybe Aroldis Chapman no one's can, but Peterson works in the low-90s with his fastball and also has a swing-and-miss slider. He's not just a bunch of great numbers, he's a legitimate prospect. At age 24 and with a half-season of success at Double-A already under his belt it's hard to imagine Peterson not reaching the majors this year if his performance is anywhere near 2014/2015 levels.

14. Alex Meyer | Reliever | DOB: 1/90 | Throws: Right | Trade: Nationals

YEAR     LV      G     GS      ERA        IP       H     HR      SO     BB
2013     AA     13     13     3.21      70.0      60      3      84     29
2014     AAA    27     27     3.52     130.1     116     10     153     64
2015     AAA    38      8     4.79      92.0     101      4     100     48

Last year at this time Alex Meyer seemed to be on the verge of joining the Twins' rotation and many people had visions of the 6-foot-9 right-hander with a mid-90s fastball developing into an ace starter. One year later there's a chance Meyer will never make a start for the Twins, let alone emerge as a top-of-the-rotation anchor. He was a mess at Triple-A early on last year, got shifted to the bullpen in mid-May, and stayed there for the remainder of the season.

Meyer has always had shaky command, which isn't unexpected with a flame-throwing giant, but his control vanished last year and even after being demoted to the bullpen he issued 4.4 walks per nine innings. He got rocked during his brief MLB debut in late June, coughing up two homers and five runs in three innings, and was not called back up. There's no doubt that Meyer's rough 2015 took a big chunk out of his prospect status, but he still has late-inning bullpen potential.

He consistently works in the mid-90s with his fastball--averaging 96 mph in his two-game Twins stint--and Meyer racked up 62 strikeouts in 55 innings as a reliever. For now the Twins haven't abandoned the idea of Meyer as a starter, but throwing 20 pitches at maximum effort a few times per week seems like his best bet to stick in the majors. And at 26 years old there's no reason for the Twins to hold him back if Meyer shows any sort of consistency as a reliever in the minors.

13. Adam Walker | Left Field | DOB: 10/91 | Bats: Right | Draft: 2012-3

YEAR     LV      PA      AVG      OBP      SLG     HR    XBH     BB     SO
2013     A-     553     .278     .319     .526     27     65     31    115
2014     A+     555     .246     .307     .436     25     45     44    156
2015     AA     560     .239     .309     .498     31     65     51    195

There's a tendency to compare low-average, high-strikeout minor leaguers like Adam Walker to successful low-average, high-strikeout major leaguers. However, that's flawed because successful low-average, high-strikeout hitters typically weren't that way in the minors. In other words, if you strike out a ton and hit .239 at Double-A like Walker did last season the expectation wouldn't be that you'd hit .239 in the majors. It'd be a lot worse.

Adam Dunn, Chris Davis, and Ryan Howard hit above .300 as minor leaguers, so expecting Walker to follow in their footsteps because his numbers in the minors look like their numbers in the majors requires a leap of faith. None of which means Walker isn't an intriguing prospect. His power potential is massive. Walker has played four pro seasons and led all four leagues in home runs, averaging 32 per 150 games. However, his strikeout rate is beyond "high."

Consider that as Double-A hitters Walker struck out 30 percent more often than Miguel Sano, whose strikeout rate is viewed as extreme. Walker also does a much worse job controlling the strike zone, drawing 51 walks compared to 195 strikeouts in 560 plate appearances last season. And those 51 walks were a career-high. Toss in iffy corner outfield defense and Walker's future essentially revolves around his ability to bash 30 homers per season off big-league pitchers.

12. Kohl Stewart | Starter | DOB: 10/94 | Throws: Right | Draft: 2013-1

YEAR     LV      G     GS      ERA        IP       H     HR      SO     BB
2013     RK      6      3     1.69      16.0      12      0      16      3
         RK+     1      1     0.00       4.0       1      0       8      1
2014     A-     19     19     2.59      87.0      75      4      62     24
2015     A+     22     22     3.20     129.1     134      2      71     45

Things have not gone according to plan for Kohl Stewart since the Twins selected him with the fourth overall pick in the 2013 draft and signed him away from a Texas A&M football scholarship for $4.5 million. He's missed time with arm problems in each of his three seasons and displayed no ability to miss bats while facing low-minors competition, showing why using top-10 draft picks on high school pitchers has such a spotty track record throughout MLB.

Stewart averaged 6.4 strikeouts per nine innings at low Single-A in 2014 and saw that dip to 4.9 strikeouts per nine innings at high Single-A last season. He was young for both levels and is still learning to pitch, but high school phenom top-five picks are supposed to rack up strikeouts and Stewart has failed to do so. Last year at Fort Myers he totaled 71 strikeouts and 45 walks in 129 innings, which would have sent Stewart plummeting down this list if not for his pedigree.

His poor strikeout rate is a major red flag, but Stewart has shown the ability to generate tons of ground balls and that skill alone contains plenty of upside. He allowed just two home runs in 553 plate appearances last year despite facing hitters older than him 90 percent of the time. Stewart's raw stuff translating to ground balls instead of strikeouts isn't what the Twins had in mind, but it still puts him on the path to long-term success if his control and durability improve.

11. Lewis Thorpe | Starter | DOB: 12/95 | Throws: Left | Sign: Australia

YEAR     LV      G     GS      ERA        IP       H     HR      SO     BB
2013     RK-    12      8     2.05      44.0      32      2      64      6
2014     A-     16     16     3.52      71.2      62      7      80     36

Thanks to an impressive mix of youth, raw stuff, and production in the low minors Australian left-hander Lewis Thorpe's prospect stock rose rapidly in 2014 only to come to a screeching halt when September elbow problems led to Tommy John surgery. He went under the knife at the end of spring training and missed the entire 2015 season, meaning he'll likely be somewhat limited in 2016 as well. At age 20 there's no need to rush his recovery timetable.

Prior to blowing out his elbow Thorpe dominated rookie-ball hitters in 2013 and then moved up to full-season competition as an 18-year-old, posting a 3.52 ERA with 80 strikeouts in 72 innings at low Single-A in 2014. He was the youngest pitcher in the Midwest League and the average hitter he faced was 22, making his already strong numbers stand out further. Even after missing an entire year Thorpe will still be among the youngest pitchers at Single-A in 2016.

Thorpe signed with the Twins for $500,000 as a 16-year-old, so his outstanding pre-surgery play matched expectations. He was on track to perhaps reach Double-A as a 19-year-old last season, but this season will be all about getting Thorpe back on track despite his no longer being on the fast track. After all, even after a totally lost season Thorpe is still two years younger than the Twins' first-round draft pick last year.