Sickel's top 20 Prospects:
1) Oscar Taveras, OF, Grade A: He’s going to be a monster as long as health issues don’t get in the way.
Left-handed-hitting Vlad Guerrero is the ceiling here.2) Carlos Martinez, RHP, Grade A-: One day over the service time limit, but I hate calculating that stuff. I use 50 innings for starters, 30 innings for relievers, so he still qualifies at 28 innings pre-season. For most teams he would be in the rotation. Assuming some slight additional command refinements and good health, he could become a number one starter or a superb closer.
3) Kolten Wong, 2B, Grade B+: Outstanding instincts, refined skills with solid second base tools. Perhaps something like Todd Walker with better defense is what I’m expecting here.
4) Stephen Piscotty, OF, Grade B+: Refined approach at the plate, only question is how much of his raw power becomes genuine home run production, which seems a typical issue with Stanford products. Personally I’m optimistic he can get to 20 homers someday with strong OBP contribution.
5) Alex Reyes, RHP, Grade B+: Aggressive grade for a rookie ball pitcher but I really like the upside here with mid-90s heat and a chance for two above-average secondary pitches to make a complete package.
6) Marco Gonzales, LHP, Grade B: Polished college lefty from Gonzaga shouldn’t need much time in the minors; I’d expect him to be a rotation candidate by 2016 if not earlier. Doesn’t have the ceiling of someone like Martinez or Reyes but his floor is high and the Cardinals have an eye for college arms.
7) Rob Kaminsky, LHP, Grade B-: Borderline B. Love the breaking ball. Fastball velocity varies but should develop into a three-pitch mid-rotation candidate. Higher grades likely once we see more innings out of him.

Tim Cooney, LHP, Grade B-: Third round 2012 pick from Wake Forest posted outstanding 125/18 K/BB ratio in Double-A last year. Throws three solid pitches for strikes, keeps hitters off-balance like a master, should fit as fourth or fifth starter on a big league team.
9) Randal Grichuk, OF, Grade B-: Acquired from the Angels in the Bourjos trade. This guy can be awful good if he makes just a bit more progress with the strike zone and I think the Cardinals are a good place for him to do that. Could be a real steal, and hey, he’s 4-for-9 so far in Triple-A with a home run.
10) Carson Kelly, C-3B, Grade B-: Grade C+: He didn’t perform too well in A-ball last year and we’ll have to see how the conversion to catching from third base works out, but I still find Kelly’s bat to be intriguing with a chance to hit for average, OBP, and power. I believe in the potential that made him a second round pick in ’12 enough to show some patience at this stage.
11) James Ramsey, OF, Grade C+: Florida State product draws raves for work ethic/makeup, most scouts seem to like him a lot despite mediocre physical tools. Hit .251/.356/.424 with 15 homers in Double-A last year, drew 53 walks but whiffed 108 times which was more than expected. For me he profiles as a solid fourth outfielder.
The top 11 guys seem obvious to me, but at this point it gets murky. The C+ types should be seen as a tier approach and not an in-cement ranking.
12) Aledmys Diaz, SS, Grade C+: Cuban defector working his way back into shape in Double-A after signing this spring. I don’t have any real idea what to expect so this is a WAG type rating until we see how the scouting reports translate into performance. Age 23, mixed reports about his defense, some say he can stay at shortstop, others disagree and project him as a 2B. Expected to hit for average with fringe-type power, will have to see about OBP. Could be anything from a regular to a utility player.
13) Zach Petrick, RHP, Grade C+: Undrafted pitcher out of University of Northwestern Ohio has turned into a genuine prospect, throws harder in pro ball than he did in college, good progress with curveball and changeup, throws strikes, posted 1.99 ERA with 122/27 K/BB in 113 innings last year. Began 2014 with five shutout innings in Double-A with eight strikeouts. Potential number four/five starter or a nice relief arm.
14) Cory Jones, RHP, Grade C+: Not a big name yet but Cardinals fans/sources are on him, posted 2.04 ERA with 52/16 K/BB in 66 innings last year in Low-A, big pitcher who throws hard and showed dramatically improved command last year.
15) Patrick Wisdom, 3B, Grade C+: Very impressive glove at third base, excellent when used at first base, but still trying to unlock his bat, hit .235/.313/.401 with 15 homers in A-ball. Supplemental ’12 first rounder from St. Mary’s has more offensive potential than he showed last year.
16) Lee Stoppelman, LHP, Grade C+ Borderline C. 24th round pick from Central Missouri in 2012 reached Triple-A in his first full season, 1.55 ERA with 78/26 K/BB and just 40 hits in 66 innings last year. Not just your ordinary LOOGY, throws three effective pitches. Started in college and in some organizations he would still be doing so.
17) Breyvic Valera, INF-OF, Grade C+: Borderline C. Sometimes you just like a guy. Best position is second base but he has experience everywhere except catcher and first base. Super-utility profile, contact hitter with .313 career average, still just 21 years old but already in the minors for five years. I think he’s pretty interesting.
18) Oscar Mercado, SS, Grade C: Borderline C+. 2013 second-rounder draws raves for defensive ability at shortstop. Did not hit well in rookie ball (.209/.290/.307) but is young enough to improve considerably and defensive skills will buy him time.
19) Vaughn Bryan, OF, Grade C: Borderline C+. 35th round pick last June, performed well in Appy League (.280/.341/.394, 13 steals). Very good tools, being hyped by some sources with understandable justification as he could develop into a 15/20 guy if all goes well. Everyone likes his athleticism but there are enough questions about offensive approach to hold me back a little until we get more data. Could rank much higher next year.
20) Edmundo Sosa, SS, Grade C: Intriguing player from Panama, hit .314/.396/.450 with good strike zone judgment in the Dominican Summer League. Decent chance to stick at shortstop, hitting approach very mature for his age. Could rank much higher six months from now.
http://www.minorleagueball.com/2014/4/6/5586364/st-louis-cardinals-top-20-prospects-for-2014