What Cardinal farmhand will have the biggest impact on the 2015 St. Louis Cardinals?

On Sunday, Overlord Humphrey ran a piece discussing the usefulness and efficacy of projection systems in determining the quality of both individual players and the rosters those players make up.  It's an excellent read and I suggest you go check it out if you missed it.  Craig then posted the Cardinals ZiPS projections yesterday on the front page when they were released, along with an overview of the what the 25 man roster looks like in terms of zWAR heading into 2015.

This morning, Ben looked the how effective the projection systems (including our crowdsourced VEB projections) were in projecting Matt Holliday's 2014 performance.  As you can see by the graphic in that piece, ZiPS pegged Holliday the best last season with nearly every other system being far more bullish on Holliday.

Given the state of the projected active big league roster, what Cardinal prospects does ZiPS expect to make the biggest impact in 2015?

Let's start with a trio of starting pitchers, providing depth to a talented rotation that's not without it's share of question marks:

Marco Gonzales:

Tyler Lyons:

Tim Cooney:

Having 8 starting pitchers who project to be 1.4 zWAR or better in 100+ innings is awfully good depth for a major league club, and that's not counting guys like Zach Petrick (1.1 zWAR) or Boone Whiting (0.9 zWAR). Are any of these guys likely to be an above average starter?  ZiPS says no, with FIP- for each coming in below 100, and as someone who has seen these three pitch a considerable amount I would concur with that.

Thing is: You don't need your 6-8 starters to be better than league average -- you just need them to be capable 5th starters should someone go down to injury or be horribly ineffective.

You'll notice that ZiPS also expects Gonzales and Lyons to get some bullpen time, based on how they have been used in the past.  That's probably a good assumption given a Cardinal bullpen with just LOOGY Randy Choate and walking question mark Kevin Siegrist serving as the arms from that side of the bump.

Given this depth it makes sense that John Mozeliak hasn't signed any one year deals for make-or-break pitchers, but should he have been looking harder at upgrading the bench?

Ty Kelly (2B/3B):

Dean Anna (SS/2B/3B):

I really don't want to imagine a world in which Anna and Kelly combine for 979 plate appearances, given that in that universe cyborgs have used the ARPANET to take over the earth and turned it into a smoldering pile of rubble Kolten Wong, Jhonny Peralta, and Matt Carpenter all miss significant time for non-Mike Matheny related reasons.

However, in that scenario, the Cardinals would be far better off in 2015 than they were in 2014, if ZiPS is to be believed. 1 zWAR players don't grow on trees, and the Cardinals plucked these two from other organizations and all it cost them was AA pitcher Sam Gaviglio, who is probably a reliever at best in a sea of power armed relievers in the organization's high minors (more on that in a minute).

Given what the Cardinals got from Daniel Descalso, Pete Kozma (0.9 zWAR for 2015, mostly on defense), and Mark Ellis a year ago, Kelly and Anna represent a significant upgrade.  Just pray that we don't need 1000 PA's between them next year.

Even with all that extra oomph off the bench, I still expect this next farmhand to have the biggest impact on the Cardinals in 2015:

Sam Tuivailala:

ZiPS projects Tooey to be worth about as much as the more heralded $6.3M duo of Jordan Walden (0.6 zWAR) and Matt Belisle (0.5 zWAR) will be worth to the Cardinals next season, and for good reason: He's got one of the best fastballs in the entire minor leagues, topping 100 mph in most all his outings a year ago.

Yes, his control needs work, as evidenced by the fairly obscene walk rate projection.  Considering that 2014 was just his second full season on the mound, however, it's safe to assume that a boost in command could happen relatively quickly and his fastball is nearly unhittable.  Does he need a second pitch?  In the long run, yes, and currently that's a work in progress.  But Jason Motte got by with just fastballs for the first couple years of his career and was pretty effective throwing four seamers 85-90% of the time given the velocity and his ability to command his fastball.

Given the attrition of the Cardinal bullpen in recent years, I could see a spot for Tooey opening up in the middle part of the year and the Cardinals haven't been shy about tossing talented pitchers into a relief role in relatively short order when needed given how they handled Trevor Rosenthal, Kevin Siegrist, Carlos Martinez, and even Shelby Miller (after a pretty poor year in AAA actually) in the last half decade or so.

If Tooey gets a chance in the middle innings, I think he could be a legit asset that Matheny and Lilliquist can use to shorted games even further.