AL SP Strikeout Rate Laggards — Last 30 Days

A week ago, I discussed some of the surprising and notable names atop the American League starting pitcher last 30 day strikeout rate leaderboard. Today, let’s check in on those pitchers that find themselves at the bottom.

In his first full season after returning from Tommy John surgery, Alex Cobb has performed respectively, on the surface, posting a 3.89 ERA. He has needed help though, as his SIERA stands at a weak 4.78, but the issue is that the strikeouts that came before the elbow injury have not reappeared. And over the last 30 days, he has been even worse at punching out batters. Unfortunately, he hasn’t even had his typical grounder rate to induce double plays given all the balls in play he is allowing. The problem here is that he has relied far more on his curve this year than his changeup/splitter, despite the latter pitch being more whifftastic and allowing a lower wOBA over his career. I don’t know if it’s elbow related or not, but he needs to get back to throwing his best pitch more frequently.

I have been a Michael Fulmer for as long as he has outperformed his SIERA so significantly, and the luck has finally neutralized over the last 30 days. His ERA over that span is well over 4.00 and almost a perfect match for his SIERA. With a mid-90s fastball and a slider and changeup that both induce swings and misses at double digit rates, it’s absurd that Fulmer has been posting such lowly strikeout rates. But he has been, and because he also continues to magically keep his fly balls in the park more frequently than the league, he remains a major risk moving forward.

After a strong showing at Triple-A, Jose Berrios finally got his second chance to prove that last year’s cup of coffee with the Twins was a fluke. Through his first 10 starts, he was solid, striking out 24.6% of the batters he faced while posting a 3.96 SIERA. But things have fallen apart in his last five, as his strikeout rate has tumbled, while his SIERA has spiked to 5.15. It’s not a pitch selection thing and while his fastball velocity chart is in a slight downward trend, it’s not enough to ring the alarm bells. It comes down simply to throwing strikes and generating whiffs – in his first 10, he posted a F-Strike% of 63.6% and SwStk% 10.7%, but since, those have plummeted to 53.2% and 6.9% respectively. That’s like the 2016 version of Berrios. So which is the real one? Please stand up.

In his first 15 starts, Sean Manaea was a strikeout machine, retiring 25.1% of the batters he faced via the K. His last five starts have seen a much less whiffy Manaea and a far less consistent one. In two of those starts, he struck out over 25% of batters, while in the remaining three, he struck out less than 11%. That’s quite a stark contract between those two groups of starts. Since he missed time earlier in the season with a shoulder issue, you just wonder about his health each time he has a poor outing with a minimal number of strikeouts.