In our gracious host's recently completed Top 20 Organizational Prospects series that previews the contents of his forthcoming Baseball Prospect Book, John doled out 282 C+ or better grades to pitching prospects. Within that lot is a subgroup of 204 pitchers who faced at least 100 batters in the 2013 minors above the Gulf Coast League (GCL) or Arizona League (AZL) and averaged at least 10 batters faced per game. They received 4 A grades, 10 A- grades, 21 B+ grades, 22 B grades, 39 B- grades, and 108 C+ grades.
In this post I will rank the 2013 minor league performances (above the GCL or AZL) of those 204 pitchers using a fielding- and ballpark-independent statistical evaluation system, and then use those performance rankings to re-allocate the 4 A grades, the 10 A- grades, 21 B+ grades, ..., and 108 C+ grades among the 204 hurlers (2013 GCL/AZLers, injury casualties, and relievers will retain their assigned grades). To wrap things up, I will list the pitchers who have the largest differences between their performance grade and prospect ranking grade.
How I Quantify Performance
Having long ago captured the intimate details of every 2013 minor league plate appearance made above the GCL and AZL, I use that information to sort each of them into one of the 12 general plate appearance outcome categories listed in the following table.
The numbers shown in the table quantify what each event type was typically worth in terms of runs in that league during 2013. For each minor league pitcher, the number of each of the 12 events they allowed is tallied and the pitcher is charged with the corresponding number of runs listed in the table for each such event. That yields a single sum over all 12 events for each pitcher that can be divided by the number of batters faced to quantify how well the pitcher did at avoiding the types of plate appearance events that are most often associated with runs. Then all of the starting-biased pitchers in a given league can be rated according to how well they did relative to the league's core reference sample of starting-biased pitchers. Ultimately each pitcher receives a single performance score for each league they appeared in and that can be weight-averaged to yield a single score for them for the entire minor league season. Here, I will simply express their performance score as a percentile (specifically the percentage of their league's or leagues' peers who they bettered or equaled; 100% is best, 0% is worst).
The process is not quite as simple as the above description suggests; I make some rather complex mathematical adjustments to the data to correct for the environment-related and human-subjectivity-related variations in event classifications that exist between individual ballparks of the same league; I also eliminate all plate appearances that resulted in a bunt or foul-out or involved a pitcher batting to further level the playing fields for the pitchers to be compared.
The 4 Pitchers to Earn a Grade A Performance Rating for 2013
So let's begin by assigning the 4 available A grades to the 4 best statistical performers of the 204 study pitchers.
Ben Lively is probably not the Reds farmhand who you would expect to find in the top spot of a table of the minor league's best pitchers of 2013. Here, Lively rises 1 and 1/3 grades versus the prospect grade John assigned him; his blazing 2014 start in the California League suggests that his 2013 performance was no small-sample or short-season-competition-fueled fluke. Jon Gray and Kevin Gausman retain their A grades. Julio Urias climbs 2/3 of a grade to grab the fourth and final available A on the wings of his astonishing 2013 pro debut.
The 10 Pitchers to Earn a Grade A- Performance Rating for 2013
Mid-season Tommy John surgery cut Roberto Osuna's 2013 short and surely contributed to his C+ prospect grade, but his work before then earned him the 5th overall rank on performance and top spot among the grade A- performers. Noah Syndergaard, Kyle Zimmer, and Kyle Crick retain their A- grade. Burch Smith ascends a full letter grade while Michael Feliz rises 2/3 of a letter. C.J. Edwards, Erik Johnson, Alex Meyer, and Marcus Stroman make a small 1/3 of a grade step up from B+.
The 21 Pitchers to Earn a Grade B+ Performance Rating for 2013
The 21 recipients of B+ performance grades include a trio of John's B+ recipients: Edwin Escobar, Tyler Glasnow, and Rafael Montero. Robert Stephenson takes a small tumble down from the exclusive grade A neighborhood to here, while Taijuan Walker and Eddie Butler drop down slightly from an A- to a B+. Clayton Blackburn was the only hurler to make the 1/3 letter skip up from a B, while 4 make the 2/3 of a grade jump from B- territory: J.R. Graham (shoulder injury casualty), Jesse Hahn, Nathan Karns, and Matt Barnes. A surprising 10 make a full letter grade leap from C+ country, with control plus batted ball outcomes standouts Kyle Hendricks and Dylan Floro leading the pack.
The 22 Pitchers to Earn a Grade B Performance Rating for 2013
Henry Owens, A.J. Cole, and Jake Odorizzi each come down a notch from a B+ grade to a B grade. Jimmy Nelson, Vince Velasquez, Pierce Johnson, and Anthony Ranaudo retain their B grades. Six climb up from a B- to a B grade and 9 rise from a C+ rating.
The 39 Pitchers to Earn a Grade B- Performance Rating for 2013
Turning attention to the 39 recipients of a B- performance grade, we find 5 former A- grade recipients: Yordano Ventura, Carlos Martinez, Aaron Sanchez, Andrew Heaney, and James Paxton (a full letter grade drop for this fivesome). Lance McCullers falls here from the B+ ranks and 5 come down from a B grade. Luke Jackson, Allen Webster, Adam Conley, Nick Tropeano, Chris Anderson, Robbie Ray, and Mike Wright hold their B- grades while 21 former C+ recipients climb up a rung to join them.
The 108 Pitchers to Earn a Grade C+ Performance Rating for 2013
We’ve reached the C+ performers now with one A grade prospect still on the lam. Surprisingly, the rogue grade A hurler doesn't surface until the 63% Performance Percentile. Despite Archie Bradley’s minuscule 1.97 AA ERA, a 1 standard deviation (SD) below league-average control rating and a half SD below average rating on batted balls offset his 1 SD above league-average strikeout rating and pulled his overall performance grade down for that portion of his campaign to slightly under league norms (49% performance percentile).
And below are the final 54 of the 204 pitchers evaluated.
With the second half of them, awarding a C+ performance grade seems rather generous; the likes of Tyler Matzek, Trevor Bauer, and Daniel Corcino would have earned F grades or thereabouts had their performance been ranked versus minor league starters in general.
The Pitchers Whose 2013 Performance Grades Most Trailed Their Pre-2014 Prospect Ranking Grades
These 15 would stand to be among 2013's most underperforming starting pitcher prospects or perhaps even today's most overrated starting pitcher prospects, per this exercise. Each of their performance grades was at least a full letter lower than their prospect grade.
The Pitchers Whose 2013 Performance Grades Most Exceeded Their Pre-2014 Prospect Ranking Grades
These 13 would stand to be among 2013's most overperforming starting pitcher prospects or perhaps even today's most underrated starting pitcher prospects, per this exercise.
At the left, I have listed the 15 pitchers who had at least a one full letter lower performance grade than John's pre-2014 prospect grade. The group to the right includes the 15 best 2013 performers of the 204 re-ranked pitchers according to the statistical evaluation system. So which group of 15 pitchers would you prefer to have in your hypothetical farm system?