I'm sensing a little entitlement here. You want a high-ceiling shortstop who's going to be called up mid-season? Guess what, there are none. Green and Franklin aren't ready yet, same with Machado. Hamilton is the fastest guy in the minors but he might not stick at SS and he played rookie ball last year, so 2013 is about what you'd expect. Dee Gordon might get a cup of coffee at the end of the year but he's got zero power.
Prospects aren't sure things. None of them. And they get called up when it makes sense for the team, not for you. If you want to invest heavily in prospects in a dynasty league where you're carrying them on your actual bench and not in a minors/reserve system, be prepared for a lot of frustration.
Anyway. I will help, since I enjoy minor league prospecting, but dial down the entitlement.
Jordan Lyles - doesn't have ace upside, but closer than most. The Astros have a terrible rotation so I could see him getting a shot sooner rather than later.
Jenrry Mejia - ace upside, but the Mets have jerked him around. He's starting for now, but a midseason callup is iffy. Lots of variability here. Could be an ace, could flame out in the bullpen.
John Lamb - Not a true ace, but has a very high floor and projects as a great #2. Could be up late in the season but not fantasy relevant till 2012.
Simon Castro - I like him a lot, and being in SD helps. I'd sleep on him though since he's not a high-profile name unless you really follow prospects. Not worth keeping on your roster all year unless he gets called up.
Jarrod Parker - Ace upside. Haven't heard much about ETA, but a late-season call up is possible.
Casey Kelly - Move to SD helps but I'm not sold yet. Has name value so if you want him you might have to grab him.
Kyle Gibson - not enough upside to worry about until he gets called up. Do you like Scott Baker, Nick Blackburn, and every other Twins pitcher outside of Liriano? Then you'll love Gibson.
Matt Moore - ace upside, but TB does not rush prospects, period. Jeremy Hellickson was dominating AAA like two years ago and he's just now getting a shot. TB is absolutely loaded with pitching, so when Moore comes up is anyone's guess.
Christian Friedrich - don't bother until he shows he's worth paying attention to. Inconsistent.
Of these guys, if I was going to carry someone all season it would be Jarrod Paker. As a "B" option I'd take Mejia if you like upside and risk or Lamb if you're more interested in certainty.
Brent Morel - he's up now, so that's something. Doesn't have huge upside.
Lonnie Chisenhall - not a lot blocking him in CLE but he doesn't have star-upside. Could be a .285, 25 HR a year type which is very solid from 3B but not a superstar.
Grant Green - Profiles as an offense-first SS and he's definitely gonna be a fantasy star if he sticks at SS, but he's a year away at least.
Dee Gordon - Could rack up the steals but he's got zero power. Also not particularly close. Possible late season call up.
Brett Lawrie - Depends where he plays. Could be a solid fantasy 3B or a great 2B. The move to Toronto helps him in my opinion. Makeup questions, or so I've heard.
Ruben Tejada - what? No.
Brett Jackson - Great all-around tools. If you want an OF out of this group, this is the guy.
Yonder Alonso - no
Jason Kipnis - Love the bat at 2B. Should be up mid-season.
Scott Cousins - no
Brandon Allen - not enough bat for 1B, but a solid floor.
Matt Dominguez - all glove, bat not exciting for a fantasy 3B. Will struggle to hit .250
Anthony Rizzo - Move to SD hurts a lot; still quite far away, though still has great upside.
Josh Reddick - no
Casper Wells - haha no
Ben Revere - no
Michael Taylor - see if he bounces back, skills usually don't totally vanish like that. But for now, no
Zack Cox - no, average bat for 3B, though worth paying attention to if he moves over to 2B.
Fernando Martinez - still some upside, but fading fast. No.
Matt LaPorta - see if he does anything this year. He's gonna get at-bats. He's not done yet.
Hank Conger - value nosedives if he doesn't stick at C. Stay away for now.
If you want a SS, Green and Gordon will both be fantasy relevant but they're a ways off. SS is a wasteland and it's no different in the minors. None of the guys on this list are elite prospects. Lawrie is probably the guy I roll the dice on here, but I wouldn't be too thrilled with it. If you want to go with a 2B Kipnis is your man - he's a bat-first 2B with adequate defense, and should be up sometime this year.