Surprises Among Last 30 Day SIERA Leaders by Mike Podhorzer August 16, 2018 Every so often, I like to peruse recent starting pitcher performance, as skills seemingly change far more often than for hitters. That’s because all it might take is an added pitch, ditching of one, or simply changing the mix. So let’s discuss some of the surprises that appear near inside the top 20 over the last 30 days, our of 93 qualified pitchers. Last 30 Day SIERA Surprises Name K% BB% GB% SwStr% ERA SIERA Nick Pivetta 35.4% 3.5% 42.6% 12.8% 3.68 2.35 Rick Porcello 29.2% 4.2% 46.2% 8.3% 3.69 2.97 Kyle Hendricks 26.2% 2.5% 48.8% 9.3% 4.45 2.98 Jack Flaherty 36.0% 10.8% 33.3% 14.4% 3.18 3.08 German Marquez 29.9% 7.5% 52.5% 14.3% 3.58 3.12 Zack Wheeler 27.3% 4.0% 39.4% 12.5% 1.33 3.17 Zack Godley 26.7% 6.1% 47.6% 12.9% 2.84 3.29 Tanner Roark 24.1% 1.8% 45.0% 9.4% 1.21 3.30 Jakob Junis 26.8% 8.0% 51.4% 9.7% 3.55 3.40 Jhoulys Chacin 26.1% 6.7% 48.7% 6.0% 3.90 3.45 You would have no idea by solely looking at his season ERA of 4.37, or even his last 30 day ERA of 3.68, but man, Nick Pivetta has been awesome this year. An inflated BABIP has hidden a major skills breakout and a SwStk% that has surged above 12%. It hasn’t been any particular standout pitch resulting in all the strikeouts, but everything he has thrown has generated an above average SwStk%, just not elite. He’s a great target for the rest of the year and assuming he came cheap in a keeper league, makes for an even better target if his owner doesn’t realize the results will soon catch up to the skills. How did Rick Porcello managed to post a near 30% strikeout rate with just an 8.3% SwStk%?! That’s one of the largest discrepancies between the two metrics I have ever seen. It makes his SIERA far less sustainable as there’s no way he could maintain such a strikeout rate without inducing significantly more swings and misses. Kyle Hendricks is exactly the same as last year, except his LOB% has fallen back to Earth. He’s been pretty elite over the last 30 days from a skills perspective, but that ERA just won’t budge. I would be more optimistic if his season SIERA was below 4.00, but once again, we have to hope he performs well in the luck metrics to deliver fantasy value. I hate making that bet. I think we all knew after his spring training performance that Jack Flaherty was a strong breakout candidate. His strikeout stuff has been otherworldly the last 30 days, just check out that SwStk%! It’s all been in his electric slider that has produced a season 22.7% SwStk%. He has also thrown two more pitches with low double digit SwStk% marks, to go along with a respectable fastball. Obviously, I don’t expect this strikeout rate to be sustainable, but he looks like a great option over the final quarter of the season. German Marquez, whaaaaaaaaaaaa?! To go along with a near 30% strikeout rate over the last 30 days, he has even generated grounders at a 50%+ clip. Marquez throws hard, so it’s not totally shocking a strikeout rate surge would eventually come, but it’s his slider that has really been the fuel here. He has upped his usage and the pitch’s SwStk% has more than doubled since last year. I’m deathly afraid of owning a Rockies pitcher, and looking at his home/away splits, I am right to be afraid. He’s been fantastic in away parks, but is it worth owning a pitcher you’ll only start half the time at most? So, Zack Wheeler is good again. Guess he’s healthy. His fastball velocity sits at a career high, which has driven a career high SwStk% and strikeout rate. I wish he’d get back his ground balls, but that’s just nit-picking. I think his rebound is real. Just when you thought Zack Godley’s season was a major disappointment, he goes and does this over the last 30 days. His ERA remains above 4.00, but showing improved control without giving up strikeout ability is a positive development. I’d hold on. Welp, it’s hard not to post an excellent SIERA when you allow just a 1.8% walk rate like Tanner Roark. That won’t continue obviously, but it’s a reminder that he’s become a forgotten man as a decent last pitcher. Remember when Jakob Junis posted mid-3.00 ERAs in both April and May? Then do you remember when he posted ERAs above 7.00 in June and July? Junis is good again, though his SwStk% doesn’t inspire much excitement. Even with the strong last 30 days, his ERA still stands near 5.00, as he has suffered from gopheritis. That’s hard to do when you pitch in a home park that’s one of the most homer suppressing in the league. I think he’s fine as an AL-Only option, but I wouldn’t feel comfortable in anything shallower. Jhoulys Chacin?! First a current Rockies pitcher, now a former one. Many of us laughed when the Brewers signed him after seemingly coming off a luck-filled season, but what do ya know…he’s doing it again! While his SIERA finally looks good over the last 30 days, a full season SIERA nearly a run higher than his ERA highlights how risky it is to continue counting on him. Oh, and that last 30 day strikeout rate is “supported” by a pathetic 6% SwStk%. It’s official — Chacin’s strikeout rate-SwStk% discrepancy is the biggest I’ve ever seen. So far, he’s getting by thanks to a low BABIP, but he has posted low BABIP marks throughout most of his career and owns a .281 career mark. That’s pretty impressive and does suggest this is a real skill. I’m not sure how he’s doing it, but it’s there. So he’s likely to keep beating his SIERA, but that still doesn’t make me want to own him.