How to Evaluate Minor League Stats

How to Evaluate Minor League Stats
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With the Minor League season entering the half-way point, the period of frequent promotions is upon us. The first wave of promotions (and demotions), occurred last week, with a number of well-known prospects being bumped up a level.  The most notable, Kris Bryant and Kyle Schwarber, who dominated their respective leagues. However, not every player moving up a level put up those sensational stat lines.  Looking past the mainstream stats can help shed light on these promotions.


Baseball is a unique sport in which a lot of numbers can be derived because each play is isolated. Unlike soccer and other sports, where there can be as many as 22 players on the pitch at the same time, baseball is simplistic. In its easiest to understand form, it is a pitcher against a hitter. There are fielders and other variables, but some advanced stats attempt to take fielders out of the game and just focus on this interaction between the pitcher and the hitter. When evaluating a prospect's stat sheet, try to steer away from counting stats such as RBI’s, runs, and pitcher wins and losses, and make stats that deal with rates the focal point of your analysis.


For pitchers, FIP, K% and BB% are a few of the stats that one should look at. K% and BB% are based on the strikeout or walk percentages of batters faced. The higher the K% a pitcher has, the less amount of times the ball is in play and a random event could occur. FIP attempts to measure what a player’s ERA should look like if balls in play were at a league average. Over time, it has been proven that a pitcher has little control over what happens when a ball is in play. Lets take a look at the Iowa Cubs pitcher Tsuyoshi Wada for reference.


Wada has never had the best stuff, but what he lacks in plus-pitches he makes up for in being very deceptive and having advanced command. This year he has posted a 2.81 ERA over 86.1 innings, a large enough sample size that we can derive some stats from his performances, but still must take them with a grain of salt. His K% and BB% are a solid 23.5% and 6.5%, yet his FIP is at 4.03.  Because ERA and FIP are calculated on the same scale, we can forecast that his ERA is going to rise because in the long-run, a pitcher’s FIP and ERA tend to be very close to each other. Don’t expect him to get promoted to the majors because his ERA is so low in AAA. He’s also 33 years old, and it’s always important to take the age of the player and his home ballpark into context when perusing stats.


No matter what Kris Bryant stat you look at, you’ll be dazzled. Advanced metrics and standard alike will show the pure havoc Bryant caused to AA pitchers this year. Just like pitchers, a hitters BB% and K% can be representative of their talent relative to their league. Bryant has always had a relatively high K%, this year he’s at 26%, but he has made up for it with his improving patience.  His BB% this year is at an above average 14.5%. Now onto the sparkle. In 297 PA’s in AA, he has posted a .347 ISO, a stat that measures a hitter's raw power. For reference, an average hitter has an ISO at .145, and anything above .250 is all-star caliber power. His wOBA (weighted on-base average), is a monstrous .505. Arguably the most impressive accomplishment of his season thus far was he produced those numbers for half a season. His promotion to Iowa was very much deserved. On the other side of the spectrum, Jeimer Candelario was recently demoted to Kane County again. Still just 20 years of age, Candelario seemed to struggle at Daytona, posting a .188/.270/.321 slash line in 64 games. However, not everything is as bad as it seems. It turns out his BABIP (Batting average of balls in play) is around .100% lower than his career average. His ISO is at a below average .133, but his line drive rate, BB% and ground ball rate are all just fine. As he gains more experience at the plate in Low-A, expect Candelario to post much better numbers in his second go around.


Numbers never tell the whole story, though. What’s arguably even more important than looking at numbers and projections is scouting. A pitcher could be putting up fantastic numbers in Low-A, but that could just be a result of him having advanced command for that specific league or being more experienced than the other players in it. As that pitcher moves up leagues, his advanced command won’t play as well for him as the hitters he is facing will also improve. Another reason to scout is to watch a pitcher’s release point and mechanics. If a pitcher has poor mechanics but multiple plus pitches, in the long run he could be plagued by arm and shoulder injuries, especially with Tommy John surgery so common amongst young pitchers this year. It’s also useful when evaluating a hitter. Some hitters may have great bat speed which helps them put up excellent numbers in the lower leagues, but they could have too long of a stroke or not enough strength in their wrists to consider them to be an elite prospect. When a prospect is promoted in the Cubs system, we can be assured that they have put up spectacular numbers and have reached all of their goals for that league.

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Tags: Cubs, Prospects, Sabermetrics, Stats

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