Surprises Among Last 30 Day SwStk% Leaders

As you are likely (hopefully) aware, I’m not a fan of small sample size analysis. In fact, it could be argued that I’m far too patient, requiring the sample size to be quite significant before I change my opinion/projection on a player. But a pitcher’s SwStk% is different. It’s a per-pitch metric, so it stabilizes rather quickly and conveys very useful information. So with that in mind, let’s browse through the SwStk% leaders over the last 30 days and look to uncover any surprise names.

Erasmo Ramirez | 16.0% SwStk%

A couple of weeks ago, I recommended Ramirez as a deep league waiver wire addition. In three starts since, he has allowed just two runs for a 1.29 ERA, though his strikeout rate was just 17.5%. In this 30 day window, his strikeout rate sits at a more respectable 21.2%. Still, that’s not exactly what you would expect from such a wonderful SwStk%. The problem here is that while he’s inducing all these swinging strikes, which is an excellent thing, both his called and foul strikes rates are well below average. And since both of those are skills too, not quite to the degree the swinging variety is, we cannot automatically expected a spike.

Still, backed by a defense that ranks first in baseball in UZR/150 and a reversal of his ground ball and fly ball rates from last year, he should continue to be an asset in deeper leagues with streaming potential in shallower versions.

Jorge de la Rosa | 13.7%

In the past, it wouldn’t have been that surprising to see da la Rosa show up on a SwStk% leader list for a random 30 day timeframe. But his SwStk% had dipped below 10% the last two seasons before rebounding this year. Actually, his full season mark would represent a career best. But like Erasmo above, de la Rosa’s strikeout rate over this range is just a mediocre 19.5%, which isn’t far below his season mark of 21.8%. Is it those missing called and foul strikes again you ask? Partially yes!

His strike rate profile is interesting, to say the least. His S/Str (Baseball-Reference.com) is fifth best in baseball and foul strike 26th best. But his called strike rate? Worst in baseball by a whopping 1.5%. That might not sound like a lot, but that’s about 7% lower than the second worst mark. It’s a pretty big gap. He’s never been good at generating called strikes, but this easily represents a career low. A strike percentage right in line with history suggests better control moving forward and that ground ball rate is nice. I think he’ll have some value in deeper leagues moving forward, which is why I continue to hold him in LABR mixed.

Jeremy Hellickson | 11.8%

After baffling the SIERA followers (me included) in 2011 and 2012, the luck Gods have had their revenge ever since. Even as his skills have improved and strikeout rate jumped, his previous BABIP suppressing and runner stranding abilities have disappeared. I wonder why…perhaps because he never actually possessed those skills to begin with and was just the random beneficiary of extraordinarily good fortune? But the move to the National League this year, even if to a hitter’s park, was intriguing. Coming off a third straight season of a rising strikeout rate, was a legitimate, skills-backed breakout in the cards?

So far, it’s been more of the same. A SIERA around 4.00 as usual, similar strikeout rate as last year, but issues with all three luck metrics pushing his ERA above 5.00. Hellickson has always posted solid swinging strike rates that hinted at strikeout rate upside that has slowly manifested. But like the names above, he typically hasn’t been adept at generating the called strike. And this year his called strike rate sits at a career low, to go along with a career high rate of swinging strikes. The Diamondbacks defense ranks in the middle of the pack in UZR/150 even with Yasmany Tomas‘ iron glove at both 3B and RF. I wouldn’t touch him in a mixed league, but he could eek out some value in NL-only leagues the rest of the way.

Alfredo Simon | 11.7%

Of all the names on this list, Simon is probably the most surprising. This is only his second season as a full time starter, and last year his SwStk% was a below league average 8.4%. Even with all these swings and misses, his strikeout rate over the last 30 days is just about league average at 20%. He’s yet another who has missed the class on inducing called strikes. Couple that with a strike percentage down significantly and I’m willing to ignore his random 30 day performance and call him a serious regression candidate for the second half. His 4.37 SIERA hints at big downside and he doesn’t punch out enough batters to provide a value floor.