What follows is how the Astros' 2013 AA starters graded out versus their Texas League peers per the Fielding and Ballpark Independent Outcomes system which I have been posting data from here at The Crawfish Boxes. A more detailed explanation as to how the scores are computed can be found in this prior FanPost that focused on the 2013 starting-biased pitchers of the Greeneville Astros and Tri-City ValleyCats. Corpus Christi is the first of the 4 full-season affiliates to be put through this statistical wringer.
What the Scores Mean
"Performance Score" amounts to the pitcher's overall grade for the Texas League portion of their season relative to other league starters and is evaluated over every plate appearance that did not feature a foulout, bunted ball in play, or pitcher batting; it effectively assumes that the 2013 Texas-League-average effect on run expectancy occurred in every instance of each of the 12 possible plate appearance outcomes (walk or hit-by-pitch = +0.32 runs, strikeout = -0.27 runs, infield flyball = -0.24 runs, groundball to batter's pull-field third of the diamond = -0.07 runs, ..., line drive to batter's center-field third of the diamond = +0.30 runs, ..., outfield flyball to batter's opposite-field third of the diamond = +0.00 runs). The three subscores (Control, Strikeout, Batted Ball) are just that - how the pitcher would rate versus league peers looking only at control, only at strikeouts, or only at batted balls. Age Score is tabulated independent of the performance measures and simply quantifies how young the pitcher was versus the league's average age for a starting pitcher in 2013. As for the numbers reported in the tables, a 50 score on any of the measures amounts to posting the league's average value (the pitcher topped or equaled 50% of peers), a 60 amounts to 1 standard deviation (SD) better than league-average (topped/equaled 83% of peers), a 70 amounts to 2 SD better than league-average (topped/equaled 97% of peers), a 40 amounts to 1 SD worse than league-average (topped/equaled 17% of peers), a 30 amounts to 2 SD worse than league-average (topped or equaled 3% of peers), and so on with any 10 point swing in a score amounting to 1 SD.
In the tables that follow, values that bettered the league average for that quantity by at least 1 SD are highlighted in green text ("very good") whereas those that trailed it by at least 1 SD are in red text ("very bad"). Asterisks indicate lefthanded throwers. The 8 pitchers in bold were official qualifiers for the study pool in so much as they faced at least 200 batters while averaging at least 10 batters faced per game (non-qualifiers do not enter into calculation of the averages and standard deviations that are used to assign scores to pitchers).
Tropeano topped the 8 qualifiers with a 59 Performance Score (81st percentile), and that would support the position that he pitched better than the 4.11 ERA and 1.34 WHIP would suggest. Martinez, Buchanan, and Doran each graded out well in the control and batted ball columns and landed just behind Tropeano. The very-young-for-AA Foltynewicz, who typically rates as the organization's 2nd to 4th best pitching prospect per most prospecting sites, placed 5th at Performance Score among the 8 Hooks' qualifiers; here, one can appreciate just how poor his control was relative to 2013 league standards. Alaniz stands out as being a rather elite performer on batted balls, and his Age Score reminds us just how young he was for AA.
The table below shows how those same pitchers' plate appearance result frequencies sort out in the Texas League portion of their campaign.
And here are the LHB splits data and the RHB splits data of the 8 qualifiers, as graded versus the league's starting pitcher peers.
Tropeano's splits numerically contradict internet banter of him being a changeup specialist whose main weakness is the lack of a quality breaking ball; the somewhat low Performance Score versus LHB suggests that his changeup might not be working as well as it had at lower levels while his outstanding RHB splits suggest that the criticisms of his breaking ball are either wrong (it is an effective pitch) or irrelevant (he has another secondary pitch that more than offsets any breaking ball deficiencies). The workmanlike Martinez was similarly solid versus LHB as versus RHB. Though similar overall to Martinez, the splits show that Buchanan was definitely better against RHB than LHB. Doran was the best of these 8 righties versus LHB (and among the top ones in the league) with the strikeout being his main weakness against RHB. Foltynewicz consistently rated close-to-average against RHB in posting three 50ish subscores, whereas the LHB splits paint him as being exceptionally poor at control and very good at strikeouts and on batted balls. Alaniz' LHB Performance Score dropped a bit relative to the RHB value as his control and strikeouts declined versus LHB while the batted ball performance held steady.
Most of these pitchers competed at other levels, and as the scores for those other clubs are compiled it will become possible to grade each pitcher's complete 2013 season in a similar fashion.