Trying To Explain Mike Fiers | Disciples of Uecker

Disciples of Uecker

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Amidst a disappointing season for the Milwaukee Brewers, several improbable storylines have bubbled to the surface. Perhaps the most intriguing storyline is how Mike Fiers went from a 22nd-round pick in the 2009 Draft to major-league starter with a 1.80 ERA in his rookie year.

No starting pitcher (min. 50 innings) has posted a lower earned run average this season.

Pitcher ERA
Mike Fiers 1.82
Brandon Beachy 2.00
Jered Weaver 2.13
Ryan Vogelsong 2.27
Jordan Zimmerman 2.45
David Price 2.49
Justin Verlander 2.51

His name appears out of place on that list, which includes some of the best pitchers in baseball. After all, his fastball barely tops out at 90 MPH and averages a mere 88.1 MPH. Few starting pitchers with below-average velocity can carve up major-league hitters — much less put up better numbers than last year’s AL MVP and Cy Young Award winner, Justin Verlander.

How has Mike Fiers translated a fringe-average repertoire into the best numbers in the league amongst starting pitchers?

The answer sought in this article is not luck, random variance, or small sample size, all of which have been bandied about within the blogosphere (and undoubtedly have some truth to them). Instead, this article is more concerned about how Fiers has performed at an elite level through 80 innings this year without above-average stuff on the mound.

In a very strict sense, Fiers has compiled a 1.80 ERA and a 2.21 FIP because he is striking out a ton of batters (9.00 K/9), walking very few (1.80 BB/9), and keeping the baseball inside the ballpark (0.34 HR/9). That combination will almost always lead to success for a starting pitcher. Very few major league starting pitchers can boast above-average ratios in all three major categories.

One of the main reasons the 27-year-old has thrived thus far has been the effectiveness of his fastball. He throws it for a strike 68.1% of the time, and opposing hitters seemingly cannot see the baseball very well out of his hand. His delivery possesses a plethora of deception — which is explained very well in this article by Nathaniel Stoltz — and his fastball also seems to rise as it reaches the plate. Of course, it does not actually rise. Gravity still pulls the baseball down as it reaches the plate. His fastball simply does not drop as much as opposing hitters expect.

His +10.14 z-Mov is above the league average, though his earlier starts this season had his vertical movement upwards of +12.0 z-Mov. That was near the league lead. His vertical movement appears to vary from start to start — as with most pitchers — but his average vertical movement on his fastball is still above-average. That causes opposing hitters to catch the baseball on the upper portion of the barrel.

Those off-center hits can be illustrated by the fact that hitters foul off 20.5% of his fastball offerings and are only put in play 17.0% of the time.

The real weapon, though, appears to be his curveball.

Opposing hitters are only hitting .120 against his curveball. To put that in perspective, that means Fiers has only surrendered six hits all season when throwing his curveball. Six.

He employs his curveball as both a strikeout and get-me-over pitch, which allows him to better keep opposing hitters off balance and off his fastball. The different purposes of the pitch can be seen in the below heat map:

The two most prominent red areas lie over the center of the plate, as well as below the strike zone. Again, the former comes when Fiers is working early in the count and flips up a curveball to get ahead. The red blips below the strike zone come later in the count, when Fiers is working to put away an opposing hitter and strike him out.

The right-hander also features a changeup to left-handed batters and a cutter/slider to right-handed hitters. Those added wrinkles have helped him continue to find success the second and third time through an opposing batting order, especially when one considers that Fiers has a 16.7% whiff rate on his changeup for the season.

It has been a magical ride for Mike Fiers in his first big-league season. He has an outside chance to win the National League Rookie of the Year — especially if he continues on this pace — and has given the organization hope for their starting rotation in 2013. Despite fringe-stuff on the mound, Fiers has found elite success, and it’s important to realize that it’s not something that can be explained away with luck or random variance. He is doing some things on the mound that are sustainable.

His home run rate needs to normalize, as he cannot sustain a 3.3% HR/FB rate for the remainder of the year (or next year), but he has proven himself to be a legitimate big league starting pitcher with a chance to stick as a mid-rotation pitcher.

And for a 27-year-old rookie pitcher who agreed to turn professional for a mere $2,500 signing bonus, that’s pretty incredible.

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Tell us what do you think.

  1. Matt Tracy says: August 10, 2012

    Unrelated to Mike, let me say this: “z-Mov” has always bothered me as a stat. Not because I don’t understand it, but because it’s a some-what silly name for the stat. The ball never varies along the z-axis, unless it’s hit before it reaches the catcher (allowing for a minor variance in a “spiked” curve ball). Yes, there is change as the ball travels from pitcher to cathcer “along” the z-axis, but those changes should be represented in x and y changes.

    Maybe the fault lies in my understanding, but the x and y axis measurements should be “inside/outside” and “high/low”, respectively; right? the z-axis to the path perpendicular to both, from the mound to home.

    Sorry, small complaint about something barely related to the article.

    • Alex Poterack says: August 10, 2012

      When I did multivariate calc, graphs were always drawn such that the floor is an x-y plane, and the z-axis represented height. I would agree with you that, since we’re usually only concerned with in-out and high-low in a pitch graph, and really use it as a 2D graph, it would make sense to use x and y for the axes we’re interested in, and save z for the one we aren’t interested in. But I suspect this convention is why it’s referred to as “z-Mov”.

  2. Mike says: August 10, 2012

    Hard to say Fiers is “without above average stuff” when his curveball is that nasty.


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