Discussing Five Last 30 Day Starting Pitcher K% Leaders

As we head into the final month of the season, let’s discuss five qualified starting pitchers that appear inside the top 20 in strikeout rate over the last 30 days.

Blake Snell | SDP | 41.4% K%

Typically, a move from the American League to the National League would be a major positive for a pitcher, as he goes from having to face the DH a majority of the time to the opposing pitcher. Unfortunately, that expected boost hasn’t been enjoyed by Snell, as even after a 1.71 ERA over his last 30 days hasn’t been enough to avoid sitting with the highest ERA of his career. His skills have degraded as his SIERA is over 4.00 for the first time since 2017, while his walk rate has spiked to the highest mark of his career.

He hasn’t enjoyed that AL to NL strikeout rate bump, at least on a season long basis. But over his last 30 days, his strikeout rate has skyrocketed to an absurd 41.4%. That includes three of five starts with double digit strikeouts, and one just missing at nine. His fastball velocity hasn’t moved much, but he’s ditched his changeup, and upped the usage of his slider. Given his history, you would expect that switch to increase his strikeout rate, as his changeup has generated the lowest SwStk% out of his three non-fastballs (changeup, curveball, and slider). As a left-hander, you figure he would need that changeup on right-handed batters, though he does still throw his curveball, but not very often.

For his career, his slider has been his best whiff pitch and this year is no different. It’s not as easy as thinking he should just throw his best pitch more and its effectiveness could decrease with higher usage. But it’s clearly worked so far. I wouldn’t expect a 40%+ strikeout rate to continue, obviously, but I think a higher strikeout rate than he had posted earlier in the season should continue to be in the cards if he keeps his slider usage this high.

Nathan Eovaldi | BOS | 32.0% K%

It took a while, but Eovaldi’s strikeout rate has come closer to the levels we would expect given his fastball velocity. For the season, he has posted skill marks right in line with his previous couple of years, but he’s taken his strikeout rate up several notches over the last 30 days.

Though is pitch mix has been inconsistent from start to start, the only clear change he has made is upping the usage of his curveball at the expense of his cutter. Historically, his curve generated a slightly higher SwStk% than his cutter, but the gap has widened this year. Still, of his curve, slider, and splitter, the curve is at the bottom of the trio in SwStk% by a small margin, so perhaps he could mix it up and favor his slider or splitter during any particular game moving forward.

With a strong fastball now that induces whiffs, Eovaldi owns a deep mix, though without a true standout strikeout pitch. I think he’ll continue to mix it up each game depending on which of his non-fastballs feels best on that day and he’s got options given that he throws four of them, all of which have generated a double digit SwStk%.

Triston McKenzie | CLE | 31.9% K%

After a demotion to Triple-A in mid-June and amid a bout with right shoulder fatigue in late August, McKenzie has been significantly better in recent months. Most of that is due to regaining his control, as his walk rate was over 20% before his mid-June demotion.

He hasn’t changed his pitch mix much since earlier in the year, but there is definitely a difference in his stuff. Before his demotion, he averaged 91.7 MPH with his fastball, but after, he’s been at 92.8 MPH. Over his last 30 days, he’s maintained the same increased velocity. That is back in line with where he was last year during his impressive debut. Luckily, the shoulder issue hasn’t affected him as he sat at 93 MPH in his last start.

During his professional career, control has never been an issue for him so it was odd to see him struggle with it so much earlier in the season and even at Triple-A. Everything else is back to normal though as he continues to generate swings and misses, his velocity is fine, and he’s getting strikeouts. The one risk here is the extreme fly ball rate. It should help keep his BABIP down, but could lead to outings where he allows a couple of homers and he torpedoes your ERA.

Logan Webb | SFG | 31.7% K%

Webb is one of the spring training winners who telegraphed his breakout. His skill set is drool-worthy, as it combines good control, a strong strikeout rate, and an elite ground ball rate. I can’t even find a good historical comp for him because he simply does everything better than the guys I thought might work (like Felix Hernandez and Brandon Webb).

Over the last 30 days, Webb’s velocity has remained rather stable, but he has changed his pitch mix a bit. He has cut down even further on his four-seamer, in favor of his sinker, while throwing his changeup less often and upping the usage of his curveball. His four-seamer didn’t generate a much higher rate of whiffs than his sinker, but the difference in ground ball rate is staggering. So it doesn’t make sense for him to continue throwing the four-seamer.

Both his curveball and changeup have generated double digit SwStk% marks, but his curveball has been absolutely elite sporting a 20.5% mark. You think of curves as generating called strikes more often, so it’s impressive to find his pitch sitting with a mark just over 20%. His history is too short to see if his curveball has always been more effective at inducing whiffs than the changeup, but it certainly has been this year, so it makes sense to widen the gap between the usage of those two pitches.

Webb owns a perfect skill set right now and he’s a great example of why you shouldn’t completely ignore spring training stats. No, his 0.53 ERA over 17 innings was not the stat to focus on. You could have ignored that. But his 36% strikeout rate versus just a 3.3% walk rate and 2:1 ground out to fly out ratio were metrics worth noting, while still acknowledging that 17 innings is the smallest of samples.

Tylor Megill | NYM | 26.5% K%

I completely glossed over the news when Megill was recalled. I never heard of the guy and he was ranked just 23rd among Mets prospects. But his minor league stats were pretty impressive, as his lowest strikeout rate was 27.5% and he posted some pretty impressive SwStk% during his last three minor league stints at Double-A and Triple-A. Sometimes you need to just ignore the scouting and focus on the results. If a pitcher manages to generate that high a rate of whiffs in the minors and strike out such a high rate of batters, chances are he’ll be able to whiff batters at a better than average rate in the Majors too.

Over the last 30 days, Megill’s strikeout rate is no different than his season line. So I didn’t call him out here given stronger recent performance, but to highlight him for the first time in any of my posts.

His fastball has averaged 94.5 MPH and he has complemented that with a changeup and slider. Apparently that velocity is a big step up from where he used to sit, so averaging that rather than peaking at it completely changes his future outlook. Now, his mix seems like a standard repertoire with above average fastball velocity. So far, both his changeup and slider have generated double digit SwStk% marks, with his changeup near elite at 19.5%. Oddly, his changeup doesn’t even appear in the tool grades, so I’m not sure if this is a new pitch or he had thrown it too infrequently in the past to be worth grading.

Given the big velocity spike that he has maintained all season, I don’t see anything fluky here. Sometimes pitchers come out of nowhere, but usually there’s an identifiable change. In Megill’s case, it’s a velocity bump, so he’s now worthy of a roster spot in all leagues.