Changing up the pitch mix: What’s worked for the Colorado Rockies

Statistical observations from the change in pitch mix

It’s hard to doubt that the move away from fastballs in favor of more offspeed pitches has been a negative for the starters as a whole. Every pitcher has seen improvement in their park adjusted stats (ERA- and FIP-) and those stats as a whole show that so far it’s working well. So what should we expect the rest of the way?

As a whole, the staff has seen their K% increase from 18.8% to 19.6%. This has been driven mostly by increases from Marquez (24.3% to 30.7%) and Senzatela (13.1% to 19.4%). We’ll likely see Marquez’s K% drop a couple points while Senzatela’s will probably hover around that number as his 2019 rate seems to be an outlier. If you’re thinking about why the staff’s increase in K% isn’t higher given the increases from those two, that’s because Gray’s numbers have dropped from 23.5% to 10.6%. Freeland’s K% of 15.7% isn’t too far from his career norm, but there may be room for improvement. As a staff, this rate shouldn’t drop much.

There’s going to be some regression, though. The staff has been overperforming to a degree and a couple stats that point to this are their BABIP (Batting Average on Balls In Play) and Hard Hit Percentage.

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For BABIP, the staff has a combined for a number of .232. That’s the second-best in MLB with only the Twins posting a better number. What it suggests is that the Rockies have had an element of luck on balls in play. A lot of that is a result of defensive superiority from guys like Nolan Arenado, Trevor Story, and David Dahl. That shouldn’t be a shock to anyone. But it’s an improvement from the last three years which saw BABIPs of .313, .297, and .305. The best BABIP in the past few years by starters was .265 by the Braves in 2018, so we should expect negative regression there.

Rockies starters are also getting hit surprisingly hard given the results they’re putting up. Their current Hard Hit Percentage of 45.8% ranks as the third-highest in the Majors behind only the Diamondbacks and Rays. Thankfully for the Rockies, a large amount of batted balls have resulted in ground balls (47.6%, seventh-best in the Majors). And a high Hard Hit Percentage doesn’t always equate to bad performance, but it doesn’t exactly help things either. The three teams with the highest hard hit percentage last year (Angels, Giants, Diamondbacks) ranked 30th, 22nd, and 13th in ERA-, respectively. If the Rockies keep getting groundballs, they’ll be fine.

Another stat to keep an eye on is the Rockies current HR per Fly Ball rate of 9.3%. That number is crazy low. The best number put up in recent years is 10.3% by the Cardinals starters in 2018. For the Rockies, we saw rates of 15.7% in 2017 and 13.9% in 2018, so we know numbers close to that should result in playoff caliber pitching. What we don’t want to see happen is a rate of 20.8%, which we saw in 2019. That’s unlikely to happen again, but what these numbers show us is that the Rockies’ change in pitch mix has resulted in less hard contact on fly balls, which is a very good thing.

We should expect it to increase from where it’s at, but it shouldn’t get to 2019 levels where we want to bash our heads in after yet another three-run home run that puts the Rockies in an 8-0 hole in the 3rd inning.