In his first 14 starts this season, Lucas Harrell looked like a good pitcher. He was able to generate ground balls with a pretty good two-seam fastball and was learning how to pitch deeper into games and become a solid part of this rotation.
In the last seven starts, though, he's gone crazy. He's struck out 46 in the last 45 2/3 innings. That's a strikeout rate of 9 per nine innings. In those first 14 starts? His rate was HALF that. 4.4 per 9 innings. After Sunday's game, I asked Harrell about his increased strikeout total. He told me that the biggest change was he's been getting ahead in counts more often and that puts him in a good situation to get more strikeouts.
As good, analytical baseball fans that we are, we can't just accept that as a pitcher "maturing" or any sort of filler language on what changed. We want to know how Harrell has so dramatically increased his strikeout rate, keeping it much higher than even his minor league rates. We want to know whether it's sustainable.
Luckily, we have the means to figure this out, thanks to Texas Leaguers' Pitch F/X data. Take a quick journey with me through those numbers to figure out what changed in Harrrell's approach over these starts. We'll also check the validity of Harrell's claim that it was simply an increase in his 0-1 counts that led to better strikeout numbers.
Here's what he did in his last seven starts:
And what he did in the first 14:
First of all, we need to note how good his two-seam fastball has been. It's his most effective pitch and the one he's thrown most often. That's led to the pitch becoming one of the top 15 two-seamers in the entire league. He's in the same class as Cliff Lee, Jered Weaver and C.J. Wilson with the pitch.
The biggest change, though, is that Harrell has shelved his four-seam fastball in favor of his slider. Using a two-seam/slider combo has proven very effective, even if his slider has lost a little whiffiness. But, the change has also increased the effectiveness of that four-seamer. By using it less, he's missing more bats with it.
There's also been a huge increase in how effective the change and curve have been when he breaks those out (which is rare). Here's what I think happens: Harrell is throwing the two-seamer, trying to get ground balls. However, his out pitch can be any one of four pitches, including the slider, four-seamer, change and curve. By changing up when he uses those, he's able to beat his scouting report a little and keep batters off-balance.
Let's look at the slider itself over those starts via some Pitch F/X graphs. Here's the slider in the first 14:
And the last seven:
As you can see, the biggest change is that the slider has tightened up quite a bit. It's been much more consistent over the past seven starts, with less downward movement. That suggests he's cleaned it up, probably through his mechanics.
That was one of the points he made on Sunday, that he didn't feel good about his arm action. Consistency there could easily lead to consistency with this pitch, and may explain why he's had this short term success. The other side of this is a more consistently breaking slider could help him differentiate between the change and curve, making those pitches better in the process.
The big question is whether a more consistent slider is actually been a better pitch, or if it's just taken the league a while to catch up to it. If he's really been able to refine it, I'd say the increase is much more sustainable.
So, what about his assertion that it was all about getting ahead in the count?
First 14: 167 0-1 counts, 46.5 percent
Last 7: 91 0-1 counts, 48.6 percent
Yep, not real change there. Maybe the plan is to get ahead in the count, and Harrell feels he's doing that more consistently lately. Perception can turn into reality, especially for a pitcher in the middle of a start.
However, the more likely reason his strikeout rate has spiked is the slider's effectiveness. Next time I see him, I'll ask about it and see if I get a different answer.