Mark Rogers’ Repertoire, Illustrated

Milwaukee right-hander Mark Rogers made his sixth start on Sunday since his late-July recall from Brewers Triple-A affiliate Nashville — and, while he was slightly less impressive yesterday (5.0 IP, 4.66 xFIP) than in previous outings, Rogers both (a) allowed zero runs (which is kinda the best number of runs a pitcher can allow) and (b) escaped with a still very reasonable 89 xFIP- through 33.2 innings.

The start was notable, as it represented Rogers’ first appearance in front of one of the league’s excellent center-field cameras, thus giving the best view yet of Rogers’ repertoire.

What follows is an occasionally competent examination of that repertoire.


Entering Sunday, Rogers’ fastball had averaged 94.0 mph exactly through five starts, notable in itself for a pitcher who lost all of 2007 and 2008 — and much of 2011 — to various arm injuries. That velocity was down on Sunday, which saw Rogers sit more in the 91-92 range and only just touch 94 (as opposed to 97-98, as in previous outings).

The PITCHf/x algorithm identifies both a four- and two-seam fastball in Rogers’ repertoire, although, as the following chart (of Rogers’ complete repertoire this season) illustrates, there isn’t much practical difference between the two.

Whether Rogers is actually throwing two fastballs is immaterial, really, as there’s little distinction between them either in terms of velocity (ca. 90-96 mph) or movement. Rogers throws his fastball with more or less average horizontal and vertical movement relative to the league.

Here’s a fairly typical fastball from Rogers, a 93 mph offering to Pedro Alvarez in the second inning, a pitch he elevates for a swinging strike three:


The slider has been Rogers’ best pitch in terms of linear-weight run values so far. As I note below while discussing Rogers’ curveball, the slider isn’t a static pitch, but one whose velocity Rogers alters over rather a wide range.

Here, for example, is Rogers’ hardest breaking ball from Sunday, a third-inning 0-1 pitch to Andrew McCutchen at 86 mph:

And here’s a slider thrown at 81 mph for a swinging strike, from later in that same plate appearance. This pitch features more break — both horizontally and vertically — than the previous one, but it’s the same kind of break, and mostly indistinguishable from the slider above in that regard.


Rogers is noted in more than one internet place for throwing both a slider and a curve — and, in fact, the PITCHf/x algorithm classifies the pitches separately, as well. Just as we saw a 5 mph difference between the two sliders above, however, it’s more likely the case that Rogers’ curveball is merely a slower version of his slider, as the two pitches assume basically the same “shape.”

As an illustration, consider the PITCHf/x chart above, with its two distinct clusters, and then this one, courtesy Roy Halladay:

Halladay’s chart clearly reveals the presence of four — or, at the least, three and a half — different pitches. While Rogers’ breaking balls are classified differently, they’re all situated along a pretty clear continuum.

To get a sense of the occasional randomness of pitch classification, consider this graph, which shows the velocity of all Rogers’ curves and sliders from Sunday:

All of the pitches to the right of the line were classified as sliders; all the pitches to the left (except one), as curves. Yet, it wouldn’t be entirely shocking were that same distinction to be made, and that same line to be drawn, three or five data points to the left. Rogers, essentially, is “tricking” PITCHf/x into two separate classifications, whereas what’s actually happening is he’s throwing a similar pitch with different velocities.

In any case, here’s an example of that slower breaking ball, a 74 mph pitch to Rod Barajas in the second inning for a called strike:


Rogers threw a lone and lonely changeup on Sunday.


Data from Brooks Baseball was very helpful in the composition of this piece.

Carson Cistulli has published a book of aphorisms called Spirited Ejaculations of a New Enthusiast.

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10 years ago

Do you take requests for things like these?