Last 30 Day SIERA Improvers by Mike Podhorzer June 27, 2019 Pitcher skill levels change far more quickly than hitter skill levels, thanks to the many ways they could improve, or decline. A pitcher could add a new pitch that immediately becomes effective, or similarly, stop throwing a pitch that had been ineffective. A pitcher could also gain or lose velocity. A pitcher could also reposition himself on the pitching rubber or even decide to pitch from the stretch or the windup regardless of situation. So let’s check in on the most dramatic SIERA improvers over the last 30 days compared with the period leading up to that date range. Last 30 Day SIERA Improvers Name Through 5-26 K% Last 30 Days K% Through 5-26 BB% Last 30 Days BB% Through 5-26 SIERA Last 30 Days SIERA SIERA Diff Brad Keller 16.6% 18.4% 11.1% 4.8% 5.29 4.12 -1.17 Walker Buehler 28.4% 36.6% 3.7% 1.5% 3.38 2.41 -0.97 Merrill Kelly 19.6% 23.7% 6.9% 3.2% 4.69 3.77 -0.92 Lance Lynn 25.7% 30.6% 5.9% 3.8% 3.89 3.15 -0.74 Adrian Sampson 18.6% 24.3% 5.1% 4.0% 4.55 3.89 -0.66 Dylan Bundy 24.8% 27.4% 7.8% 4.8% 4.26 3.65 -0.61 Chris Sale 35.4% 38.8% 5.9% 3.9% 2.92 2.37 -0.55 Jeff Samardzija 19.4% 20.2% 7.1% 4.8% 4.84 4.29 -0.55 Yu Darvish 26.3% 25.4% 12.7% 7.6% 4.62 4.12 -0.50 Brad Keller was an easy bust candidate after last year’s surprise 3.08 ERA. Those results were not supported by his skills, as his 4.51 SIERA would attest. He’s got the ground ball rate, but brings nothing else to make us believe he’s any good. In the last 30 days though, he has enjoyed a marginal jump in strikeout rate (though even that was still well below the league average) and drastically sharpened control. Those strikeout and walk rates, combined with the worm-killing skills, would actually make him playable in AL-Only leagues if he could sustain the gains. He certainly has help from his home ballpark and excellent defense. Man has Walker Buehler been on a roll! His strikeout rate has gone through the roof, while he has cut his already elite walk rate to a microscopic level. There’s no obvious trend in his pitch selection and his velocity has remained pretty stable. So he’s simply getting better results from his excellent repertoire. It’s doubtful he keeps a walk rate this low and I’m ever so slightly concerned about the loss of grounders, but he’s obviously proving that last year was no fluke and there will not be a sophomore slump. Returning to MLB after playing for years in Korea, Merrill Kelly was a complete wildcard heading into the season. Some considered him a sleeper as unknowns like him could yield nice profits as they typically come cheap. He opened the season with rather meh skills, but has improved them to the point that he’s been startable in shallow mixed leagues. The walk rate ain’t going to stick, but could the strikeout rate? He has been throwing his cutter a bit more, but the pitch only generates a high single digit SwStk%. His velocity has mostly been higher than earlier in the year, save for his June 18th start against the Rockies when his fastball velocity hit a season low. His SwStk% has risen from a lowly 8.5% to a far more respectable 11.2%, so that’s clearly driving the strikeout rate higher. Personally, I think his stuff is fine, he has no particular batted ball tilt, and his control over the last 30 days is going to regress. So sure, I’d consider him as a streaming option in shallow leagues, but one with little potential to stay on my team. I could never understand how Lance Lynn had been so effective relying so heavily on his fastball. Now, Lynn is sitting pretty with a career best SwStk% (fourth straight increase) and strikeout rate. He’s listened to me, as for the season, he has cut his sinker usage to a career low and is throwing his cutter more than ever before. The big change here is the surge in velocity, which now sits at a career high. That’s not just a last 30 day thing. In fact, he seemingly hasn’t done much differently the last 30 days, though his SwStk% has now remained in the double digits for seven straight starts. That’s amazing considering in the nine starts he made previously, only twice did he reach double digits in SwStk%. I’m not counting on that elite walk rate to be sustained, but less reliance on his fastball and added velocity when he does throw it is a great sign that the skills surge could continue. Adrian Sampson?! That’s an impressive spike in strikeout rate, going from well below average to above average. That suddenly makes him a consideration in shallow mixed leagues. His slider has been excellent at inducing whiffs, while his fastball has been weak, while his changeup has been below average as well. So it’s all about the slider, but he’s kept his pitch mix almost the exact same during both periods in the table. Given a history of weak strikeout rates and a fly ball tendency in a hitter’s park, I’m inclined to sit this one out. Heck, I’d be nervous even taking a chance in AL-Only leagues, as I usually just prefer to play it safe with a quality middle reliever. Dylan Bundy pitched yesterday and his SIERA undoubtedly increased. Here’s a guy I’m dying to be traded to the National League or a more home run friendly home park. As a fly ball pitcher, pitching half his games in a home run inflated park and in the AL East is dangerous and has led to inflated HR/FB rates the last two seasons. I’m most worried about his steadily declining velocity, which could possibly be behind all the dingers allowed. Remember when everyone was panicking early about Chris Sale? He sure has gotten that ERA down in a hurry. Yesterday seemed like another typical one for those that have owned Sale all season — 10 strikeouts to just one walk, yet five runs allowed in six innings. That’ll improve his SIERA, but his owners surely don’t care. The biggest concern with Sale was his velocity, which was down significantly early in the season and even dipped below 90 mph in his second game. There’s good news and bad news. The good news is that he has settled into the 93-94 mph range, which is an improvement from the first three games. The bad news is that this still represents quite the decline from last year’s mid-95 mph average. He’s still generating all the strikeouts though, but we’ll see if the velocity drop continues to inflate his HR/FB rate. Jeff Samardzija also pitched yesterday and the start likely improved his SIERA slightly. The only real driver of the last 30 day SIERA improvement seems to be sharpened control and that’s the one skill I can’t count on to continue. Control can come and go, so over a small sample size, it’s easy to just dismiss a low walk rate over that span of starts. I’d focus on Samardzija’s weak strikeout rate and only consider him in NL-Only leagues. Funny how many pitchers on this list pitched yesterday. As I type this, I see that Yu Darvish is getting a pummeling, which is unfortunate, because he had really turned things around over his last eight starts, getting his control back in order. Since his velocity is fine and he’s still inducing swings and misses, it all comes down to the walks. Are ya feeling lucky?!