Entering 2015, one of 18 “super-dependable” (100+ IP / 4+ consecutive seasons) starting pitchers exhibited a true, consistent career arc: Tim Hudson was in the process of redefining his career, or reclaiming it, after his 2008 and 2009 injury-shortened seasons. For the Braves, he prevented 13 runs in 2011, then 10 in 2012, before a somewhat-shortened 2013 campaign dropped him to one run prevented; after free agency, Hudson served as one of three below average pitchers on the 2014 Champion Giants four-man rotation. His 20 run shift over the years was hardly a shift at all compared to Edinson Volquez or Mike Leake or even Cole Hamels; in fact, among those super-dependable starters, Hudson was one of the most consistent and predictable.
|Dependable Fluctuations||2011-2014 Shift||High / Low Runs Prevented|
|E. Volquez||99 R shift||+8 (2014) / -42 (2013)|
|T. Wood||79 R shift||+21 (2013) / -30 (2014)|
|I. Kennedy||72 R shift||+33 (2011) / -22 (2013)|
|R. Vogelsong||70 R shift||+15 (2011) / -32 (2013)|
|T. Lincecum||65 R shift||+20 (2011) / -33 (2012)|
|J. Niese||52 R shift||+11 (2012) / -17 (2011)|
|C. Hamels||51 R shift||+33 (2011) / +7 (2013)|
|Y. Gallardo||42 R shift||+16 (2012) / -7 (2013)|
|K. Lohse||41 R shift||+24 (2012) / +4 (2014)|
|M. Leake||34 R shift||+10 (2013) / -5 (2012)|
|M. Latos||33 R shift||+20 (2012) / +1 (2011)|
|J. Zimmermann||30 R shift||+25 (’14 / ’12) / +13 (2011)|
|Z. Greinke||28 R shift||+22 (2013) / -1 (2011)|
|H. Bailey||24 R shift||+11 (2013) / -6 (2011)|
|M. Bumgarner||20 R shift||+13 (2013) / +1 (2012)|
|T. Hudson||20 R shift||+13 (2011) / -7 (2014)|
|C. Kershaw||19 R shift||+46 (2013) / +35 (2012)|
|D. Gee||18 R shift||+1 (2013) / -13 (2011)|
During a four year stretch (2011-2014), the super-dependable starters in the National League averaged 44 runs in fluctuation; the median was around 37, which reflects the fact that Volquez — the biggest shifting pitcher — is notably further from #2 (Travis Wood) than #17 (Clayton Kershaw) is from #18 (Dillon Gee). Indeed, the “bottom” of the list is much more consistent than the top of the list, but the biggest shifts will still impact the average fluctuation.
Basically, a starting pitcher that worked 100 innings in four consecutive seasons could reasonably be expected to fluctuate 9-to-11 runs in each season. Those fluctuations regularly shifted pitchers between “above average” and “below average” statuses; in fact, an elite group of only six pitchers managed to pitch at an “above average” rate in each of the four seasons: Kershaw, Jordan Zimmermann, Hamels, Kyle Lohse, Madison Bumgarner, and Mat Latos. Even these pitchers fluctuated at different rates: Hamels shifted between “elite” and “slightly above average” territory; Bumgarner hummed along at a consistent, but not elite, rate; Zimmermann and Kershaw were consistently elite.
Dependable starting pitchers fluctuate from year-to-year.
Why does this matter?
After the Cardinals cuffed around Wily Peralta, again, the Brewers official site called Peralta’s 2015 campaign a “down year.” This instantly set me off: Peralta, now a dependable starter with his third consecutive 100+ IP season, was hardly having a down year compared to, say, his 2013 campaign (-21 runs prevented). Now that‘s a down year; against the 2015 NL/Miller Park, Peralta is basically a handful of runs below average, which means that he will need to completely implode to catch 2013 and enter “replacement-worthy,” or “down year” territory.
It is more accurate to say that Peralta is fluctuating in 2015: the righty improved mightily last year, when he prevented three runs for the steady-if-not-spectacular Brewers rotation. He climbed significantly, so perhaps -5 runs prevented looks “bad” this year, but in the context of the league, that’s basically a fluctuation one might expect from a starting pitcher.
This might seem like splitting hairs, or playing language games, but I assure you that this is no such game: now that the Brewers have a significant core of controllable pitchers, Brewers fans must get used to these types of regular fluctuations year-after-year. This type of shift may, or may not, happen to Taylor Jungmann and Jimmy Nelson; it could certainly happen to Matt Garza, if he fluctuates to a rebound year; it may very well happen to several of the key young prospects that the Brewers graduate and groom in 2016, 2017, 2018, and 2019.
|2015 100+ IP Brewers||IP||Runs Prevented||Change from 2014|
|Taylor Jungmann||106.3||10||+10 (+106.3 IP)|
|Mike Fiers||118||-1||-15 R (+47 IP)|
|Jimmy Nelson||175.3||-2||+8 R (+106 IP)|
|Wily Peralta||104||-5||-8 R (-94 IP)|
|Kyle Lohse||144.3||-27||-31 R (-54 IP)|
|Matt Garza||148.7||-32||-30 R (-15 IP)|
Of course, by now you’re probably protesting, “Peralta’s strike outs are down.” This is very true: the righty is not missing bats in 2015, as his swinging strike % is down, while he’s allowing more hard hit balls. What’s intriguing about this episode is the steady nature of Peralta’s groundball:flyball:line drive constellation. His general trends for batted balls are steady, even if the “hard hit” and “soft hit” categories are changing the impact of those outcomes. According to TexasLeaguers, his release point is regularly changing since his injury, which may also help to explain some of his inconsistencies (it is both “stacked” and “flat, spread out“).
It is too easy to suggest that if Peralta finds his release point once again, that his command and therefore results will improve. But, it is worth speculating whether the righty has truly been able to repeat his mechanics since his injury. (In this sense, the official site and Peralta misrepresent the injury issue; Peralta keeps saying that he’s healthy, which is great, but that doesn’t mean that the injury did not impact his mechanical repetition).
So, while there are certainly explanations that one can work toward to project Peralta’s potential for improving in 2016, there is also some sense that Brewers fans and analysts ought to let the righty ride out 2015 without rushing to judgment. If Peralta puts together his stuff, mechanics, and command once again, the righty could very well improve; he’s already shown the ability to put together 20+ run improvements (as he did from 2013 to 2014). In the meantime, it is worth understanding the types of fluctuations that dependable pitchers produce on a regular basis, because Peralta himself could now be working as one of those regular, dependable starters.