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Checking in on the Pittsburgh Pirates’ slider usage

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The revolution is officially here

MLB: Pittsburgh Pirates at San Francisco Giants Cary Edmondson-USA TODAY Sports

The Pittsburgh Pirates have now firmly adopted the slider as a way of life among their starting pitchers.

On May 11th, Pittsburgh Pirates Jameson Taillon threw two sliders and the internet went nuts.

On May 22nd, he followed that up with five sliders. From there, he steadily increased his slider usage with each passing start.

The revolution had arrived. The Pittsburgh Pirates were allowing the cornerstone of their starting rotation to work in more breaking balls.

Now, nearly two months after Taillon broke the “glass ceiling” for Pirates starters, let’s check in on how the club’s starters have taken to the pitch.

Some baseline

We’ll look at all data from May 22nd onward, an arbitrary date to be sure, but as Taillon’s slider usage indicates a significant sea-change in Pittsburgh Pirates’ starter offerings, it may not be as arbitrary as it seems.

Here’s how Pirates’ starters stack up in key selected peripherals:

Selected Slider Peripherals

Metric Rate MLB rank
Metric Rate MLB rank
Usage 9.7% 15th
wOBA .267 15th
xwOBA .288 22nd
Avg. Exit Velo 86.1 mph 14th

That’s pretty middling stuff, but the effect that the adoption of a slider has shown to the club is not necessarily seen in these peripherals.

Rather, the adoption has given a new dimension to different starters.

It has made Taillon more versatile

For Taillon specifically, the introduction of a slider has turned him from a talented starter limited by pitch types to someone that can throw any pitch at any count.

Compare his offerings pre-slider to current state:

Of particular interest here with Taillon is that he can now offer four distinct pitches at several key counts, whereas he was rather predictable before.

The introduction of a slider could also have jump-started most of Taillon’s other pitches. As per FanGraphs’ pitch values, all save for the changeup have benefited from being thrown regularly alongside the slider:

Taillon weighted pitch values

Year wFB wSL wCB wCH
Year wFB wSL wCB wCH
2016 -1.6 --- 4.5 4.0
2017 -5.5 --- -0.1 -1.2
2018 11.6 2.8 2.0 -4.1

It has given Nick Kingham a foothold

The Pittsburgh Pirates introduced a slider into Nick Kingham’s repertoire this season, and it has allowed the young starter to carry a weapon in his holster immediately upon call up.

Though his last start was a bit less than encouraging, Kingham’s slider still carries a 41 percent whiff rate as per Statcast. Though this will undoubtedly regress, it bodes well for Kingham’s ability to get batters to chase. Kingham carries a 28.6 percent chase rate overall, good for fifth among all Pirates pitchers — starters or relievers.

Call it a confidence booster if you will, but Kingham’s slider has afforded him a solid - albeit shaky at times - start to his MLB career.

It has allowed Joe Musgrove to do Joe Musgrove type things

Some time ago, my colleague Alex Stumpf wrote up a fantastic look at how Joe Musgrove can throw his three different types of fastballs to all four quadrants of the strike zone.

Adding in a slider among these three types of fastball — four-seam, sinker, cutter — helps Musgrove maximize the effects of changing speeds and eye-levels of a hitter through pitch sequencing.

What also helps is that the cutter and slider carry very similar spin rates. The cut fastball comes in with a 2441 mph spin rate on average while his slider carries a 2419 mph mark. This adds deception and allows both pitches to play up.

It also allows Musgrove to mix and match locations. Here’s a look at how his slider and cutter land this season:

Here, green represents a slider while orange(ish) represents a cut fastball. Note the edges. Musgrove actually leads the Pittsburgh Pirates in called strikes (on sliders and/or cutters) with 79, or 7 percent of his total pitches, and it is easy to see why.

Other quick notes

  • Chris Archer comes to the Pittsburgh Pirates with a reputation for heavy slider usage. However, the Pirates are slowly having him incorporate more sinkers into his repertoire. Please refrain from groaning — this may actually help Archer, whose Slider has been uncharacteristically beaten up at times this year.
  • Trevor Williams has a similarly effective slider to Kingham’s, yet he still has not thrown it with any consistently substantial volume from start to start. As his effectiveness is particularly predicated on fastball command, it would be intriguing to see if Williams could integrate a slider more often as he works ahead in the count 27.1 percent of the time — compared to a 17.1 percent MLB-wide rate for starting pitchers.
  • One of the under-reported story lines for the 2018 Pittsburgh Pirates and beyond is Chad Kuhl’s future. It is anyone’s guess as to what type of pitcher that he will be upon his return. Before his injury, Kuhl’s breaking pitches worked well with each other. Perhaps instead of over-throwing upon his return to post gaudy velo, Kuhl can be convinced to let the break do more of the work.

It may have taken them a good while to get here, but it would appear that the Pittsburgh Pirates are slowly working their way towards falling in line with working in more breaking balls, with intriguing results.