2018 Leaders Review: Top 10 September Strikeout Rates: Did A Breakout Emerge?

by Eric Stashin (aka The Rotoprofessor)

We often say that September results are not indicative of what the future holds, considering the September callups helping to skew the competition level.  At the same time we’ve seen it before where a late season flourish helps to point towards future success.  With that in mind, let’s take a look at the Top 10 strikeout rates over the final month of the season to see if there is any surprises:

Strikeout Rate
1. Justin VerlanderHouston Astros13.64
2.Max ScherzerWashington Nationals13.50
3.German MarquezColorado Rockies13.38
4.Blake SnellTampa Bay Rays13.37
5.Corey KluberCleveland Indians13.34
6.Carlos CarrascoCleveland Indians12.78
7.Gerrit ColeHouston Astros12.74
8.Robbie RayArizona Diamondbacks12.40
9.Stephen StrasburgWashington Nationals11.68
10.Aaron NolaPhiladelphia Phillies11.64

For the most part it’s your standard cast of characters, with one obvious exception (and another worth touching on):


German Marquez – Colorado Rockies
Marquez was easily the biggest strikeout surprise down the stretch, with 11+ strikeouts in five of his final seven starts (9+ K in seven of his final eight starts).  The biggest difference was obviously his spike in SwStr%, with a 19.2% mark for the month (12.5% overall, 9.1% in ’17).  Was it an impressive run, or did something actually change that he can maintain moving forward?

His strikeout pitches were his slider (22.18% Whiff%) and curveball (21.14%), with the slider being a sudden development.  In fact, he had barely utilized the pitch prior to 2018:

  • 2016 – 0.00%
  • 2017 – 2.82%
  • 2018 – 18.23%

In September that was up even more, at 24.91% usage.  That doesn’t need to be an aberration and helps to show that he could actually maintain his late season strikeout surge.

There are going to be other questions, like pitching in Coors Field and the overall 37.3% Hard% he posted, and Marquez certainly deserves an in-depth look this offseason.  For now, though, in terms of his strikeouts consider us believers in his September breakout.


Robbie Ray – Arizona Diamondbacks
No one has ever doubted the strikeout stuff of Ray, the question has always been with his health and control.  Over the past three seasons he’s now posted strikeout rates of 11.25, 12.11 and 12.01, so his inclusion in this list is obviously 100% for real.

The problem is he’s seen his innings regress over this span (174.1 to 162.0 to 123.2) while his walks have ballooned (3.67 BB/9 to 3.94 to 5.09).  He did pitch at least 25.0 innings in each of the final three months (32.1 in September) and if he can stay healthy he should be a Top 10 strikeout pitcher in the league.  That’s hardly a given, however, and when coupled with the control and potential home run issues (42.0% career groundball rate) his appeal will always be capped.

Sources – Fangraphs, Brooks Baseball


  1. bbboston says:

    RP: A related comment. Clevinger a sleeper next year, IMHO.

    – 2nd Half K/9 10.5 while dialing back bb/9
    – take away two bad starts in a row in July and Clevinger’s ERA mid-2’s.

    On top of that, Clev has a pitch profile that allows him to mix things, based on what’s working for him that day and HE IS an old school SP – he battles through games with great success.

    I’m going to keep him for next year and think his k/9 will continue to bounce back and he will emerge as a true “ace”.


    • Rotoprofessor says:

      I honestly have to really dive into him (we’re taking a look at a difference Cleveland pitcher today). He has the potential, but “sleeper” may not be the right word at this point either

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