I have so many feelings about Edwin Jackson. I go back and forth wrestling with his place on the Marlins.
Could he make an impact? Some days I think yes, most days I think absolutely not. But - let's go over some basics. His xFIP over the last 3 years as a starter, 2012-2014, was 3.90 - that is just about average. Yet, his ERA over that time frame was a sub-par 5.00. Is he unlucky, or just plain bad? I mulled over this dilemma and eventually decided I had to write two articles - one about Edwin Jackson the good, and the other about Edwin Jackson the bad. Here in the first article I will talk about Edwin Jackson the good, a tale that is unfortunately so short I endearingly call it:
"The Legend of the Man with One Elite Pitch."
We will start this tale, as you would start any tale, with a chart I made looking at outcomes for each of his pitches from 2012-2014:
Let me zoom that in for you in case you missed it:
Jackson's slider - something of legend. When it produces an outcome, hitters are only batting .201/.248/.321 against it - that is fantastic. This is his strikeout pitch, with 238 out of his 447 strikeouts coming from the slider between 2012-2014. Not only is it his best pitch, but it is also elite when you compare it to other sliders around the league.
One way to analyze the effectiveness of a pitch is by looking at two sabermetric stats: whiff/swing percentage and foul/swing percentage. Essentially you are determining the number of whiffs or fouls per each swing on a particular pitch. Here are the formulas written out:
A higher whiff/swing percentage means that a pitch is more difficult to make contact on. From 2012-2014, the whiff/swing percentage on Jackson's slider was 44.40%. That is a fantastic number. To put it in perspective, Jackson finished with the third highest whiff/swing percentage on a slider in 2012 among starting pitchers with at least 200 pitches thrown, 15th in 2013, and 19th 2014. Incredible.
The foul/swing percentage on Jackson's slider during that same time frame was 26.86% - below league average. However, you have to take into account how difficult it is for a batter to even make contact with the slider. If we add Jackson's whiff/swing percentage and foul/swing percentage together, we get 71.86%, meaning that when swinging, batters only put Jackson's slider in play 28.14% of the time.
We can take this one step further by determining the probability that a pitch will be a hit after it is swung on. The BABIP for Jackson's slider is .336. To determine the probability that a sequence of events will occur, you simply multiply the probabilities of each individual event. Therefore, to determine the probability of a hit on each swing against Jackson's slider, we can multiply the BABIP by how often the slider is hit in play:
When swinging, batters only produce a hit off Jackson's slider 9.46% of the time. I will take those odds - and so will Jackson. That is why he uses the slider so frequently. Why couldn't Jackson find a niche in the bullpen? This would allow him to throw his fastball with more power or further develop a cutter, using that legendary slider as his knockout punch. Unfortunately, however, there is more to Jackson than this one pitch. I will be exploring that in the near future, but for now, let us bask in the glory of that slider.
Whiff/swing, foul/swing, and pitch usage statistics were taken from Baseball Prospectus