The evolution of Germán Márquez’s curveball

Want to know how I got the idea for today’s Rockpile topic? I was scrolling through my Twitter timeline, saw the Charlie Morton vs. Framber Valdez matchup for Game One of the World Series, and thought “wow, two of the best curveballs in baseball head-to-head!”. And then it hit me that there is a Rockies pitcher with a bender that also belongs in that elite tier. That pitcher, of course, is Germán Márquez, and this short piece will be about him and his best pitch.

The curveball has always been Germán’s best offering. His easy mid-90s fastball and plus control would’ve made him a solid prospect, but his plus-plus curveball is the pitch that made him one of the Rockies’ better prospects after being acquired from the Tampa Bay Rays. His 2018 breakthrough into a frontline starter was mainly the result of him adding a second breaking ball (a slider) to give him a true three pitch mix, of course, but we’re here to talk about that curve.

To say it’s been a productive pitch for him would be an understatement. Since 2016, among the 87 starters who’ve thrown at least 1000 curveballs, his curveball has the following ranks:

• 2nd best wOBA (weighed on-base average) allowed: .171
• 3rd most strikeouts (459) and 3rd best K% (51.7%)
• 4th best AVG and SLG against (.143 and .231 respectively)
• 2nd best OBP against (.165)

I could go on, but you get it: that beautiful breaker has been one of the best in baseball since 2016. And yet:

Baseball Savant

His decrease his curveball usage around 2018 coincided with the introduction of his slider, so it makes sense, but what is that massive 2021 drop all about? Has it been less effective? Not at all! Germán’s curve has routinely drawn whiff rates well north of 40% (which is elite) and the wOBA against the pitch hasn’t surpassed .200 since 2017. It remains a terrific pitch, he’s just... using it less. It is well documented that the Rockies have gone crazy with the slider, and Márquez is just another example of it:

Baseball Savant

I typically assume that the people in charge know more about pitching than I do, but throwing your best pitch less often seems to go exactly against what modern pitching is all about. It’s weird. Want something even weirder? Let’s take a look at the pitch’s velocity, in particular when compared to his slider (which is a terrific pitch in its own right):

Baseball Savant

That’s something you don’t see every day. The gap in velocity between Márquez’s curveball and slider has shrunk significantly over the past few seasons, to the point where they were separated by just 1 MPH in 2021 (slider averaged 86.2 MPH, curve 85.2 MPH). That’s not common, but also not unheard of, as proven by other pitchers like Lance McCullers Jr and Shane Bieber, both of whom have curveballs and slider with about 2 MPH of difference in terms of velocity. However, the thing that really makes Márquez’s curveball unique is how much its movement resembles that of his slider. Check this out:

Baseball Savant

I used this last week for my Robert Stephenson feature, but basically, yellow = slider, and blue = curveball. Do you see how clustered together Márquez’s curve and slider really are? Not only do they have virtually the same velocity, they also have nearly identical movement. It wasn’t always this way, too; here’s the same data, but for 2018:

Baseball Savant

There you can see a more noticeable difference. His slider has retained his break, but as his curveball has gained velocity, it has lost a lot of its depth. For comparison, here’s Lance McCullers Jr’s movement chart for 2021:

Baseball Savant

Now, before you yell at me, yes, I know: Coors Field hurts curveball movement a lot. I get it. But still, the difference is pretty astonishing. McCullers, who’s much more of a sidearmer than Márquez, has two distinct breaking balls, with his slider meant to sweep and his curveball meant to drop. Germán used to have a similar distinction (with less horizontal movement, obviously), but that has basically disappeared, and his curveball and slider are close to turning into one single breaking ball. I’ll be honest: there are times where I’m watching him on the mound, I’ll see a breaking pitch, and I’ll have no clue whether it was a slider or a curveball. I don’t really mean it as a negative, by the way, it’s just really weird!

Is this something good or bad? Does this need to change or not? I legitimately have no idea, because Germán has remained effective for a long time, and he was effective this season despite almost being a two-pitch pitcher in practice. That curveball has been a filthy out pitch for him for close to a decade now, so I’m not sure there’s a lot that needs to be tweaked, but who knows? Put this piece under the “cool information, pretty graphics and data, usefulness up for debate” column, folks!

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Dusty Baker, Job Security, and the Hall of Fame | FanGraphs

I know a lot of people won’t like to hear it, but I’m rooting for the Astros in the World Series. The reason? Their manager, of course! Dusty Baker, who’s always been one of the best people in baseball, finally gets another well-deserved shot at a ring as a manager, 19 years after falling to the Angels in seven games. You can think whatever you want to think about the whole cheating thing, but I know this: nobody I know is rooting against Dusty.

6 important facts to know for World Series | MLB.com

The whole “Braves breaking pitches vs. Astros fastball-hitting lineup” dynamic is very interesting to. Who y’all got in the Fall Classic?

On The Farm

Salt River Rafters: Day off on Monday, October 25 and Tuesday, October 26.

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