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Is Trevor Cahill a Big Loss? Part Three

December 18, 2011

This is an unintended third part now discussing whether or not Trevor Cahill‘s departure is indeed a significant loss to the Oakland A’s rotation or is he an easily replaceable pitcher that we just received someone with ace potential (Jarrod Parker) in return for. If you are curious at reading Part One or Part Two you can click those links. Yesterday in a very good post at Bullpen Banter by my co-host on TarpTalk: An Oakland A’s Podcast David Wiers, he argues that he

“was a bit underwhelmed with the package the A’s got in return [for Cahill]. Not because [he is] down on Jarrod Parker, Collin Cowgill and Ryan Cook, but because [he] foresaw greater things in Cahill’s future.”

The crux of his argument then follows that Cahill had very high K% rates throughout his MiLB career, and he misses a lot of bats meaning that there is nothing to stop his K% from rising again in the future at the Major League level. He uses a statistic from StatCorner called oMs% which is the percentage of swings outside the strike zone that hitters whiff on. He highlights that in 2011 the rfor oMs% to K% (among qualified starting pitchers) is 0.5144 which to me indicates a mixed correlation (far from strong but it does exist to a degree) – and given the context of the piece Wiers disagrees with me here. Cahill’s oMs% is very high (32.8%) and is similar to other pitchers with high K% – for example the other pitcher with an exact 32.8% oMs% is Madison Bumgarner of the Giants. However, it was this sentence that led me to a hypothesis:

“For context, here are the 5 closest above and below Cahill’s oMs%. I’ve chosen to list K% as well to show the strong correlation between the two statistics. Cahill and [Luke] Hochevar are clearly the outliers.”

This made me wonder, what is it that Hochevar and Cahill have in common that could explain why they are outliers. I felt that it was the sinker as Hochevar too throws a mean sinker. While FanGraphs disagreed with me as to how reliant upon the sinker the pitchers were (between 2009-2011 Cahill used it 35.7% of the time to Hochevar’s 16.9%) my hypothesis did lead me to this article from Royals Review by Scott McKinney in 2008 where correctly writes,

“Sinkerballers tend to have a unique statistical profile.  They have high a high ground ball percentage, low fly ball percentage and a pretty good ERA despite their often low strikeout rates.  Their ERA’s are typically lower than their FIP because their ability to induce poor contact, and particularly groundballs, allows them to out-perform their strikeout and walk rates. “

He also highlights some other sinkerballers, many of whom populate the list of pitchers who threw the most sinkers as a percentage since Cahill’s 2009 debut. That list is here:

2009-2011 SI% K/9 BB/9 HR/9 ERA FIP 2011 oMs%
Westbrook 56.4% 5.4 3.3 0.8 4.43 4.24 25.0%
Kendrick 49.4% 4.4 2.5 1.2 4.08 4.66 15.1%
Masterson 43.9% 7.1 3.4 0.6 4.04 3.69 28.4%
Hudson 42.9% 6.1 2.7 0.7 3.07 3.76 35.1%
Lowe 41.7% 6.0 3.0 0.8 4.57 3.89 29.1%
Cook 40.6% 4.4 4.4 0.9 4.94 4.57 25.6%
Leake 36.7% 6.2 2.6 1.2 4.03 4.43 27.1%
Cahill 35.7% 5.5 3.4 1.0 3.91 4.51 32.8%
Carmona 35.2% 5.4 3.5 0.9 4.91 4.57 28.0%
Lohse 34.3% 5.5 2.6 0.9 4.52 4.10 21.7%
Duensing 34.1% 5.9 2.8 0.9 3.97 4.10 28.5%
Volstad 33.3% 5.9 5.9 1.2 4.88 4.64 29.4%
Marquis 32.3% 4.9 3.3 0.8 4.54 4.31 22.6%
Kuroda 31.7% 7.1 2.1 0.9 3.35 3.54 35.0%
Pineiro 31.3% 4.6 1.7 0.7 4.06 3.77 21.2%

What becomes clear is that first off, the ERA/FIP rule doesn’t apply as neatly as expected and most of these guys have fewer swinging strikes outside of the zone than Cahill. Which leads to another question, just how important is swinging and missing outside the zone really given the mixed correlation? Clearly Wiers sees him becoming more of a Tim Hudson or Hiroki Kuroda whereas I see him basically staying the same and being like most of the other pitchers on this list. The differences however are quite extreme between these guys. First and foremost stands out the walks, Kuroda walks far fewer (2.1 BB/9) than Hudson (2.7 BB/9) or Cahill (3.4 BB/9) while striking out more (7.1 K/9 to 6.1 K/9 to 5.5 K/9) that is significant. Both Kuroda (0.9 HR/9) and Hudson (0.7 HR/9) allow fewer home runs than Cahill (1.0 HR/9) and have lower HR/FB’s (9.8% for Kuroda, 11.1% for Hudson and 12.1% for Cahill) despite the fact that while still pitcher friendly both Turner Field and Dodger Stadium are less friendly to pitchers with the long ball than is O.Co Coliseum.

Furthermore while Cahill does a great job of getting guys to swing and miss outside the strike zone, perhaps that more is a denominator reflection as of these three pitchers at least he has a significantly lower percentage of batters even swinging at his slop outside the zone (24.2%) in comparison to Kuroda (34.5%) or Hudson (28.2%). This of course could be a reflection of a very good pitch too however, one that appears in the zone before diving out, whereas Kuroda’s or Hudson’s are more apparently instantly as being ball or strike, after all of the three pitchers Cahill features the most horizontal movement.

All said and done, while I disagree that Cahill suddenly becomes a strikeout machine, there are reasons to believe he will see nominal improvement with age. The things that separate him from a Hudson or Kuroda to me are far more significant than the things that would have him becoming just another Jake Westbrook, because perhaps 2011 is an outlier: Cahill’s oMs% was 23.5% in 2009 and 25.2% in 2010. Perhaps his higher K/9 this year is merely a result of that strange blip which is merely a statistical anomaly as opposed to a change in pitching style. Regardless, while the results FIP-wise were better in 2011 (4.10) than in 2010  (4.19) his huge increase in oMs% and subsequent significant increase in K/9 didn’t ultimately move the needle much on his overall performance. Is there really room for Cahill to grow? Overall Cahill missed a lot more bats in 2011 (7.9%) than in 2010 (6.2%) can he really achieve an even greater jump beyond? I just don’t see it. But let’s say he has a similar jump, thus far it has only net him 0.09 off his FIP. How significant does his jump need to be to offset what will surely be an even higher HR/9 rate (despite the fact it is high as is given where he is pitching) and a very mixed record of showing an ability to keep batters from getting free passes?

A lot needs to go right for Trevor Cahill to turn into K-Hill and see an improvement in his overall utility. While Wiers’ numbers here are very interesting and thought-provoking ultimately in results the outcomes are very minimal. Cahill is an inning-eating fourth starter and it would take him becoming a completely different pitcher than he had ever been before to change it. Remember Tim Hudson, who is realistically a best case scenario for Cahill, had big K/9 numbers in MiLB too (8.7), and like Cahill they were better the lower in the system he was. Perhaps this chart proves, that Cahill is a Hudson strikeout wise, and needs to become a Hudson walks and home runs wise before we ever start considering him a front-line starter.

  A K/9 A+ K/9 AA  K/9 AAA K/9 MiLB K/9 MLB K/9
Cahill 10.0 10.6 8.0 N/A 9.9 5.5
Hudson 11.6 10.8 7.2 9.6 8.7 6.1

While ultimately any correlation between Hochevar and Cahill being on that list seems more coincidental than meaningful, it helped shed light on other pitchers with similar repertoire’s that could hold the key to Cahill unlocking something and becoming a much better pitcher. Unfortunately Cahill is dealing with a whole separate class of locks.

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