Tall people like Logan always have contort into weird shapes to fit in frame. (Photo by sideonecincy on Flickr)

27-year old right handed giant Logan Ondrusek is starting to become a bullpen staple for the Redlegs, as he’s pitched exactly 120 innings over the last two years. In the beginning of 2011 Ondrusek looked exceptionally good, but unfortunately declined as the season progressed, and ended up taking about two weeks off with a forearm injury in August. By ERA, Ondrusek seemed to stay pretty golden until some rough outings in late July/early August helped prompt his DL trip. Looking at other stats, though, it seems that Logan’s troubles started a bit earlier. His K/9 dropped precipitously in the month of June, and never recovered to April/May levels, and his WHIP increased steadily from May to August.

Looking at his 2010 splits – it seems that Ondrusek had some midseason woes the previous season as well, but recovered with a pretty solid September, unlike this year.

I also took a look at the texasleaguers pitchfX charts, which, actually just raised more questions.

Here’s a look at the different pitches, separated out by periods of two months, with a little blue guide-line to help illustrate my point:

There may be some pitch recognition issues, here, but it’s still clear that, in general, those pitches with serious left-ward movement and almost no drop disappear somewhere between May and August.  Ok, and here’s what confuses me. PitchFx is calling them sinkers. I know that Ondrusek is supposed to throw a sinker, and I mean, I am by no means an expert on  pitching, but I always thought sinkers were supposed to… sink? At least sink MORE than the four-seam fastball.

Ondrusek’s ‘sinkers’ sink less than his fastball, and, indeed, pitchFx assures me that the league average vertical movement on a sinker is a lot lower than Ondrusek’s.  Ondrusek’s ‘sinker’ is also coming in about 1 mph faster than what they’re calling his four-seamer, as I said before, a lot of leftward movement, and a really high spin rate compared to his other pitches (although pitchfX just calculates that from movement and velocity, and so it can’t pick up spin not in the direction of the movement.)

So, what is it? Do I have just zero understanding of how sinkers work? Is it a mistake fastball? Is the ‘SI’ pitch really the four-seamer with some aggressive screwball movement, and the ‘FF’ pitch  really the two-seam fastball or sinker?

And why did it disappear after two months? Is it related to his August injury? It seems maybe plausible that throwing whatever-it-is gave him some forearm issues, then he stops throwing it, but the injury lingers and he ends up on the DL a couple months later. Of course, it seems pretty plausible that it’s not that. At all.

Is it why Ondrusek was so good in April and May? Or at least, why he struck so many guys out? Fangraphs pitch value calculations, which are based on the same data, seem to have that pitch as being pretty valuable – slightly more valuable than the fastball, and much better than any of the other pitches. The ‘sinker’ itself doesn’t appear to have induced a lot of swings-and-misses – in April/May Ondrusek’s sinker had a 63% strike rate, a 48% swing rate, and only an 8.5% whiff rate. It may have had an indirect effect – as Ondrusek got a lot fewer whiffs with his ‘four-seam’ and ‘cut’ fastballs in the latter parts of the season, and both of those pitches have a lot of right-ward movement. Maybe Logan is able to use the sinker-pitch to throw batters off the scent of some of his other offerings. Still, of course, there’s an equally, if not much more convincing argument, that there’s minimal or no relation between all of these things.

In conclusion, I have no conclusion. But I certainly hope that we’re not running into a situation where Logan can’t throw an important pitch of his because it’s giving him forearm troubles. I’m going to go ahead and believe that’s not the case, because honestly, there’s, at best, a tenuous indication that is is, and it makes me feel better to believe it’s not. Also, what am I gonna do if the Reds’ third best right handed reliever is only so-so? Clearly, we’ll be terrible.