Baseball Prospectus 1996
Fortunately, the truth has a way of breaking down barriers, and today all but the most traditional of baseball observers admit that statistics for minor league hitters, when adjusted for context, are a significant source of information on that player's ability.
However, interpreting statistics for minor league pitchers has been more problematic. In part, this is because interpreting statistics for major league pitchers is more complex than for hitters. In particular, projecting future performance for a pitcher is more difficult and far less accurate than for a hitter.
The unnatural character of the pitching motion is a major reason for this unpredictability. Pitchers are much more likely to suffer a career-threatening injury than hitters, and those pitchers who do return from major elbow or shoulder surgery are unlikely to be as effective as they were before they went under the knife. And for every pitcher who takes his arm to Dr. Jobe, there are two more who fall for the cliches their coaches spit out along with their tobacco, decide to 'tough it out' and 'pitch through the pain', and end up losing their effectiveness permanently.
Projecting a pitcher's future performance is further warped by the paradoxical nature of pitching statistics. While a pitcher's won-loss record and ERA may have some value in evaluating his current effectiveness, they are not the best predictors of future performance. Other statistics, in particular a pitcher's strikeout-to-walk ratio, are far more important tools.
All of the qualifiers surrounding these predictions are magnified when minor league pitchers are projected. Injuries, common at the big-league level, are endemic in the minors; young, undeveloped, overworked pitchers are just begging for a torn rotator cuff. The road to the Show is littered with the arms of can't-miss phenoms who got hurt.
Other factors affect how a young pitcher develops and makes evaluating them more difficult. Pitchers constantly refine their craft. One may develop a changeup during winter ball, and another may learn how to throw a nasty forkball. His roommate may decide to junk his curveball and go back to the slider he threw in college. A struggling prospect may get away from a pitching coach in rookie ball who was trying to teach him to throw over the top, instead of his more natural three-quarters delivery. And any of them may suddenly wake up one April morning with 5 more MPH added to or subtracted from his fastball.
In addition to all of the above, there are also problems in trying to precisely measure a pitcher's current talent level. The usual factors (park effects, league context) that affect a position player's numbers also affect pitchers, but other influences, such as the quality of defense behind a pitcher, must be taken into account as well.
However, all the problems inherent in evaluating young pitchers should not discourage attempts to do so. While the margin of error is much greater than with similar attempts on young hitters, methods for measuring a pitcher's future potential can be devised which are more accurate than using scouts' reports that 'this guy's got a real fluid delivery' or 'he's got a sneaky-quick fastball.'
The Organizational Pitching Reports are just such an attempt. Unlike most evaluations of minor league hitters, the OPRs do not attempt to translate a pitcher's minor league numbers into their major league equivalent. Rather, they attempt to assign a prospect grade to each pitcher based on his performance in a number of different relevant categories.
The unpredictable nature of pitchers led to this approach. A pitcher with one dominant trait does not fare well in this system; rather, across-the-board performance is favored. A pitcher with a great ERA but more walks than strikeouts has a weakness that will, more likely than not, be exploited in the near future, and he can't be considered a strong prospect. Similarly, a pitcher with great control but who gives up 12 hits a game is going to be in trouble as he ascends the minor league ladder.
In addition to the categories that measure a pitcher's performance on the mound, there are various measures of context that must be introduced. A pitcher who spent all of last year in AAA is closer to the majors than his counterpart in A-ball, and is less likely to be derailed on his way to the major leagues.
Age is also an important factor; it means something that the hot shot blowing people away in the Florida State League is a 25-year-old who's been pitching professionally for several years. On the other hand, if a 22-year-old is holding his own in the American Association, then he deserves credit for that.
The scores a pitcher receives in each of nine different categories are totaled, and his final grade, from A+ to F, is determined. Depending on how high a grade each prospect earns, his organization is then awarded points, allowing each major league franchise to be ranked according to the wealth of pitching talent they have ripening in the minors.
It usually takes two or three years before most of these minor leaguers have an impact at the major league level, but some of the top prospects should contribute in a big way as early as this season. A year ago at this time, the OPR system ranked Jason Isringhausen, Carlos Perez and Brad Radke, none of whom were particularly well thought of at the time, as their organization's best pitching prospect.
Of course, the system was also enamored with Scott Standish, Brett Hinchliffe, and Blaine Beatty last year, which proves that evaluating minor league pitchers is as much an art as a science, and that much work still needs to be done. It's a good start, though.
LVL: Level a pitcher worked at. If he worked at more than one, his score is weighted by time spent at the different levels.
AGE: Points are awarded for a pitcher's age relative to the level he worked at. For example, a 23-year-old who pitched at AAA would recieve the same score as a 22-year-old who pitched at AA.
IP: Innings pitched. A minimum of 50, up to a maximum positive score for 170 innings.
WORK: Workload. This penalizes pitchers whose organizations have forced them to throw more innings than their arms can take, given their age. As pitchers get older, their endurance increases, so that while a 180-inning year penalizes a 20-year-old, a 24-year-old can pitch up to 200 innings with no penalty.
ADJ: An adjustment for the park and league the pitcher worked in, which enables, for example, pitchers in the hitter-happy Pacific Coast League to be compared fairly to those in the pitcher-friendly Florida State League. This also accounts for pitcher's who toiled in extreme hitter's or pitcher's parks.
H/G: Hits allowed per nine innings.
K/BB: Strikeout-to-walk ratio.
K/9: Strikeouts per nine innings.
ERA: Earned run average.