RADIO
Maybe this isn’t the best time to write this. He just gave up eight earned runs (ER) in a wild game at home against the Detroit Tigers, a team that currently ranks 27th in runs per game and 25th by weighted on-base average (wOBA).
Or maybe that makes this the perfect time to write this, because it captures the essence of who we know to be … Carlos Rodon.
He’s perpetually teased us with his alluring promise — the same that made him the third overall pick in the 2014 MLB draft — convincing us that he’s finally “figured it out,” only to pull the football away as we finally start to believe. He’s Chicago’s version of Michael Piñata (H/T Sporer).
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A New Rodon
Even if it’s the same up-and-down act we’ve come to expect from him, he looks different:
Now we’re talking — could Rodon be going the way of McCullers-ing? He’s leaning on his slider more this season than ever before, throwing it nearly 40% of the time through April, essentially canning his sinker in the process. In fact, only two pitchers have thrown the slider more than Rodon so far this season.
This is notably because, well, you guessed it — his slider is his best pitch! Consider his pitches from 2018:
| Fourseam | Sinker | Slider | Change | |
| Frequency | 49% | 11% | 26% | 14% |
| PERCENTILES | ||||
| ACES | 40% | 34% | 75% | 69% |
| Whiffs | 35% | 74% | 66% | 18% |
| GB+PU% | 35% | 26% | 86% | 83% |
The slider ranked well above average by ACES (velocity, movement and command), whiffs and grounders last season. And while his sinker — a pitch typically thrown to generate grounders — was relatively good for whiffs, it was also in the bottom quarter of the league by grounders and ACES.
Sure, the slider velocity isn’t great, but research by Tom Tango suggests that velocity isn’t as crucial for the pitch, so long as it isn’t “slow” (roughly 82 MPH; Rodon’s is 83-84). It also has plus movement, both in terms of run (horizontal) and drop (vertical):
| Type | Percentile |
| Velocity | 37% |
| H Mov | 76% |
| V Mov | 83% |
You can see that drop on full display here in his strikeout of Yandy Diaz, a hitter with a better-than-average strikeout rate:
Going into Friday’s start against the Tigers, his slider ranked 85th percentile by whiffs and 76th percentile by called strikes plus whiffs (CSW).
One thing to note, however, is his struggle to regain his previous velocity so far:
Worse, his slider was down another tick in his start against Detroit, perhaps driving the measly 14% whiff rate on the pitch (previous whiff rate was 23% on the season).
Maybe the fastball velocity decline is what’s driving Rodon’s usage of the slider. After throwing 49 sliders in six innings of one-run ball against the Indians on April 3rd, he said that it’s not an intentional plan to feature the slider more, telling The Athletic’s ($) James Fegan, “We didn’t roll out of bed and say, ‘Aw screw it, we’re throwing more sliders than fastballs.’” Rather, it’s a function of early-season baseball as he works to regain his previous fastball velocity.
He’s not wrong — he’s been sitting 91 so far on the fastball compared to 93-94 last season. Even so, McCann doesn’t believe Rodon will be going the way of McCullers-ing, telling Fegan after that same Cleveland start:
“I wouldn’t say we’re going to abandon his fastball and become a (Lance) McCullers who throws breaking balls 60 percent of the time. I don’t think that’s the type of pitcher Carlos is. But his last outing is an example of how he can make an adjustment on the fly and if he doesn’t have command of the fastball that day or his fastball doesn’t feel great, he can pitch off his slider and the results are there.”
Although … maybe he should? While there’s research to suggest that sliders might elevate your risk for injury, Rodon featuring his best pitch more is something we all want to see — I suppose everyone except for him and his catcher … at least for now.
Quick Hits - Other Notable Changes
Martin Perez (TEX)
Perez has introduced a new cutter that he’s now throwing 33% of the time, decreasing his sinker usage and dropping the slider in the process. The cutter is producing above-average whiffs so far, something the slider failed to do much of last season (6th percentile). He should consider turfing his below-average curveball, too.
Collin McHugh (HOU)
McHugh is McCullers-ing (Rodon-ing?), too! He's now featuring his slider more than any other pitch and over 40% of the time. Given it generates an above-average 22% whiff rate (15% is league average for the pitch), it's hard to argue against the approach. Perhaps the Astros know something about maximizing the stuff of their pitchers?
Marcus Stroman (TOR)
Groundball-machine Marcus Stroman is doing the same, emphasizing that nice slider! Like McHugh, he's now throwing his slider more than any other pitch and nearly 40% of the time. I’ll take the tradeoff — while his grounders have decreased from 62% to 54% thus far, he’s increased his strikeout rate from 17% to 24%. The slider — with its above-average 20% whiff rate — has been a key driver behind that.
