Earned Run Average - Player Analysis
Stat of the Week
by Peter Liubicich
Earned Run Average - Player Analysis
This post was written by Peter Liubicich on April 19, 2012
Posted Under: Stat of the Week

Since Monday’s column, Stephen Strasburg’s Earned Run Average (ERA) went up from 0.69 to 1.42.  This is only one instance of many, in my opinion, where you can’t judge a pitcher’s effectiveness by their ERA until after two months into the season.

Here is the formula again for ERA:

A pitcher’s ERA will usually highly fluctuate until a pitcher racks up more innings pitched, increasing the denominator, and flattening the volatility of ERA overall.  This is seen more commonly in relief pitchers as they are often only in the game for one inning, and with the rise of lefty specialists, one batter, and it takes them longer to get enough Innings Pitched to bring down their ERA.

In the case of Stephen Strasburg, in his first two starts he allowed one Earned Run in 13 Innings of work, good for an ERA of 0.69.  After Monday’s start against the Houston Astros, the Nationals ace allowed two Earned Runs in 6 innings which increased Strasburg’s ERA by almost half a run to 1.42.  Remember that ERA projects how many runs a pitcher would be expected to give up over 9 innings of work and serves as an indicator of how well, or poorly, a pitcher has performed in a season.  Judging the first three starts of the season is way too soon to say that Strasburg is headed toward Cy Young contention, but it is good to see one of the most prized prospects in baseball to come back from a tough injury and perform well.

Now, let’s take a quick look at two of the youngest, most dominant pitchers in the game today, Felix Hernandez of the Seattle Mariners, and Clayton Kershaw of the Los Angeles Dodgers.  We’ll take a look at their performance in terms of ERA the last three years, as that time frame serves as a good snapshot of a pitcher’s previous performance.

Felix Hernandez

Clayton Kershaw

I included each pitchers’ games started the past three seasons to show how reliable they have been for their team, which is huge when you know that your best pitcher will be on the mound every fifth day.  You’ll see in Felix Hernandez’s stats, the amount of Earned Runs he allowed in 2011 was 27 runs greater than the previous year.  This was reflected in his ERA as it increased by over a run, and could be attributed to King Felix allowing 19 Home Runs, and his Groundball to Flyball Ratio (GB/FB) being almost even (1.02), when in previous years he would get more groundballs than flyballs and his GB/FB ratio was higher (1.13 and 1.19).

Kershaw, the 2011 NL Cy Young Award Winner, has been a model of consistency the past three years by posting an ERA under 3.00 every year and increasing his workload each year.  One aspect of Kershaw’s success that I witnessed when I was fortunate enough to see him make a start at Good Year Park during Spring Training, is the late hitch in his delivery.  For a batter, they load their weight on their back leg to generate power after the pitcher breaks his hands during the delivery.  Kershaw breaks up this timing by differentiating his time to throw the ball to the plate with a hitch in his delivery after he breaks his hands (which you can see in this video here), throwing off the hitter’s rhythm and leaving many frustrated.  It will be interesting to see if Kershaw will keep this up, but there are no indications that the 24 year-old Dodger ace is going to slow down anytime soon, and it’s scary to think of what he could do when he hits his prime.

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Reader Comments


  1. Ground Balls  on April 29th, 2012 @ 7:17 pm

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