Thearon W. Henderson
Keep in mind that this is not a traditional top prospect list because it focuses entirely on 2012 contributions. I rank guys according to advanced metrics which, for position players, include batting runs above average, positional adjustment, defense, and a replacement level calculation that scales the total to "Wins Above Replacement" (though the concept of replacement level doesn't really apply to minor leaguers). I use a standard "runs allowed based" WAR formula for pitchers.
3) Nick Maronde, 22, LHSP/LHRP - 3.9 WAR, +24 runs saved. 99.2 IP, 2.26 ERA, 82 hits, 90 K/19 BB
Maronde was useful to the big league club sooner than anyone expected:
He excels at spotting his FB to both sides of the plate, alternating frequently, and can aggressively pitch inside against righties to keep them from getting too comfortable. He didn't make a lot of mistakes with the fastball, and consistently got ahead in the count against everyone all year. In the California League, that was enough to chew up righties and lefties alike. When he did get into a (rare) jam against a mostly righty San Jose lineup (the only one of his Cal League games that was televised), he showed smarts by pitching backwards, getting ahead in the count with his slider and change, which the opposition hadn't seen much of. He then froze a couple of guys with two-strike FB's for called strike three's. That was nifty.
However, he didn't spend enough time in AA or the majors for us to really get a sense of how he'd cope with upper-level right handers. He made some of the minor's best lefties look silly, fanning Oscar Taveras on three pitches at one point, and Jonathon Singleton on four. He chewed up Kolten Wong a number of times (though Wong adapted by jumping on first pitch FB's). Texas League righties were a different matter: Maronde still got ahead in the count frequently with that FB, but just couldn't finish them off. They didn't seem to have much trouble picking up the off speed stuff coming, or Maronde wouldn't quite elevate the FB enough to get a swinging strike. When he did have success with his slider against righties, it tended to be weak contact rather than swings and misses. To me, it looks like he slows his arm speed with his change-up, and he didn't get many swinging strikes with it. With Arkansas, he wound up K'ing only 12% of the right handers he faced.
The sample size was small, and he always seemed to be pitching from ahead in the count, so maybe his struggles putting guys away were just bad luck. But my sense was that he needed to make an adjustment, and he didn't have enough time in the Texas League to figure it out.
Maronde could be a lefty specialist right now, but he's going to need time in the minors to develop into something more. Dipoto just went out and spent a good chunk of Arte's money on bullpen pieces to buy him that time. I still see him as a potential starter, but elbow troubles and the weak change-up might force him into the bullpen for good.
2) Angel Guerra, 19, RHSP - 4.4 WAR, +24 runs saved. 118.1 IP, 1.90 ERA, 93 hits, 98 K/23 BB
My apologies to Guerra for burying him like this, but I don't have much to say about him specifically. No scouting report, no outrageous k-rate, no mind-boggling ground ball totals to report (though he was above average in that regard). I'm at a loss.
And honestly, the real reason that he's way the heck up here in the ranking is the new formula that I used for pitchers' WAR. If I'd used the same algorithm as I had in the last two years, he'd have finished with only 2.8 WAR, which in his case seems a more meaningful value to compare with his stateside peers.
The advantage of the new formula is that it weights the value of each run that a starter gives up both by taking into account the league run environment and the individual starter's ability to shape the run environment for games that they pitch. It's a simple concept, really: starting pitchers who yield one or two runs in seven innings provide a better chance for their team to win than a reliever who gives up the same number of runs in shorter outings across many games, because in low scoring games each marginal run prevented is worth more than in the average game (though that isn't true for high leverage situations; fortunately, there are other ways to assign value to those runs). An extreme example of this phenomenom is the pitcher who holds the opposition to one run over a nine inning start; he is more likely to provide a win than a team that scores 15 runs in a game, but would be considered only ~4 runs better than average while the lineup would be about 10 runs better than average. In that case, the runs in each situation don't hold the same value. The old formula had bothered me for years because of this, but fortunately people much smarter than I am addressed the problem. They merged league run environment with the run environment each starting pitcher creates, on average, and then weight the value of the runs he saves compared to their peers.
There are unintended consequences. In a run environment as barren as the Dominican Summer League, an effective starter's ability to keep marginal runs off the board has a magnified effect, similar to that of a really good college softball pitcher who can literally dominate games and singlehandedly bring home championships. I have no doubt that the new formula captured Guerra's value to the DSL Angels, who won their second straight division title and challenged for the league championship despite having no offense to speak of. However, the point of this whole exercise is to make valid comparisons of performance across leagues and run environments, and in that sense we have to consider Guerra as an outlier.
DSL pitchers who don't break the k-per-inning barrier tend to wind up as organizational arms. Think Manny Correa, Orangel Arenas, and now Gabriel Perez. That's not to say that the trend can't end any time, just that Guerra faces long odds if he's going to be the guy who does it.