Friday, August 17, 2012

Sustainable Performance

              Every year, we hear about players who have done something during the offseason or made some kind of change in their game to produce better results.  Sometimes, better performance just happens.  Over a short period of time, lots of things can happen.  The trick is determining whose performance is sustainable over a longer period of time.  We have some tools to predict this sort of thing, and I will now regale you with examples!  Not really.  Just two examples.  Will Smith and Alcides Escobar.  A pitcher and a hitter because I like completeness.

             Will Smith made a few starts before the All-Star Break, but I will be citing statistics gathered in his 6 starts since the ASB.  Keep in mind that since his stats are in only 6 games, in which he pitched 39 innings, the small sample size rule applies.

              According to Dave Cameron, a prominent figure of FanGraphs (please, if you have any interest in baseball statistics, which I hope you do since you are reading this, visit FanGraphs), there are only a few metrics we should use in order to determine a pitcher's skill.  There are only so many things a pitcher can control, so we use metrics that best capture what a pitcher can control.  The statistics are these (definitions from Dave Cameron):  K% (strikeouts per total batters faced), BB% (walks per total batters faced), GB% (groundballs per balls in play), HR/FB% (home runs per fly balls in play), and LOB% (runners left on base per number of baserunners).  I am adding in LD% (line drives per balls in play) because about 75% of line drives result in hits, but a pitcher has less control over this stat than the others mentioned.  I just think it's interesting.  It's also useful for evaluating hitters, which I will do later.

Here is a table showing Will Smith's performance in these metrics compared to the league average.

Will Smith
League Average

              The only category that is a concern is the K%.  His K% is significantly lower than league average, which means he favors the pitch-to-contact strategy.  This strategy will theoretically lead to more baserunners, which means Will Smith must strand more baserunners than average in order to maintain league average performance.  Smith does in fact strand slightly more baserunners than league average.  In addition, Smith is allowing fewer home runs than league average, which is great and is helping him prevent runs.

              In order for Smith to sustain his current performance, which is close-to-slightly-worse than league average in those 6 starts, he must either continue to strand baserunners above league average or increase his K% closer to league average.  In addition, he must keep his HR/FB% around where it is.  Reducing his LD% and increasing his GB% will also help maintain performance or even improve it slightly.  Generally, pitchers tend to regress to the mean in LOB%, so the most reliable way for Smith to sustain his overall performance would be to increase his K%.

              As a shortstop, Alcides Escobar is not expected to hit very much.  Most of a shortstop's value is tied to his defense since SS is a premium defensive position.  In 2011, Escobar didn't do much hitting, but he made plenty of highlight reels and ESPN Top 10 Plays for his defense.  However, in 2012 Escobar's offensive performance has taken a great leap, and in predictable fashion I am going to present some numbers to explain what's going on.

             The triple slash line is one of my favorite ways to gauge the offensive performance of a hitter.  It isn't really the best, but I like the snapshot I get from the triple slash line.  The triple slash line goes like this:  Batting average/On-base percentage/Slugging percentage.  In one little line, I get roughly how often that player gets a base hit (batting average has a lot of problems, but a topic for another time), how often a player doesn't make an out, and roughly how much power a player has.

             Escobar's triple slash line from 2011:  .254/.290/.343.  2012:  .301/.339/.409.  League Average SS in 2012:  .255/.309/.374.  Escobar was below average offensively in 2011, and above average offensively in 2012 compared to the average SS.

             Like I said earlier, about 75% of line drives go for hits, and it's the opposite for ground balls and fly balls.  A batter with higher LD% should theoretically get more hits.  From 2011 to 2012, Escobar has increased his LD% by about 4 points (18.1% to 22.3%), which is a significant amount; the league average LD% for SS is 20.8%.  Escobar has reduced his FB% (fly ball percentage) by about 4 points.  Escobar's GB% is about the same.

             Escobar seems to be making better contact this year compared to last year, and the better contact he is making is going for a hit more often.  Escobar's 2011 BABIP was .285, and his BABIP this year is .357.  A .357 BABIP is absurdly high and generally unsustainable.  Escobar is due for some regression to the mean (league average SS BABIP is .293), but if he can keep his LD% where it is, he should sustain an above average BABIP as well as offensive performance above the league average for shortstops.

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