Red Sox Starter Rick Porcello Can Still Be Dominant

For the remainder of the 2015 season, the Boston Red Sox will be trying to determine what players represent the future of the franchise. The starting rotation has been a disaster this season, but there have been glimmers of hope. Ian York breaks down the latest start by Red Sox starter Rick Porcello.

Rick Porcello started 20 games for the Red Sox before being put on the 15-day disabled list on August 2. He did not pitch well in those 20 games; in fact he was pretty bad, and there was a sense that his DL stint was for general suck rather than the official triceps strain. Porcello’s two rehab starts in the minors were underwhelming (two games, between single-A Lowell and triple-A Pawtucket: 9 ⅓ innings, six hits, three earned runs, one walk, and six strikeouts). It is safe to say that few people eagerly anticipated his return to the majors.

But on August 26, Porcello pitched like the ace the Sox had hoped they signed: seven innings, five hits, no walks, no runs and five strikeouts. Of course, he has pitched good games in a Sox uniform before, and followed them up with disasters, so it is far too soon to say he has turned any corners without some objective evidence in the pitch data. Is there any such evidence?

In particular, was there anything different about Porcello’s bread and butter pitch, the two-seam fastball (or sinker)? There has been a narrative this year that Porcello is not throwing his two-seam fastball often enough, or with enough confidence (whatever that means), even though there is no obvious correlation between his two-seam usage and his success on the mound. On August 26, although he used his two-seam somewhat more than usual, it was not much different from some of his previous games (such as on June 20) when his results were not particularly good. (This chart uses data from, to reduce the effect of PITCHf/x misclassification of Porcello’s pitches.)

Porcello Latest Start IMG 1

Here is a look at Porcello’s pitches, game by game in 2015, comparing velocity to spin direction (which determines the direction the ball breaks). Velocity is shown as the distance from the center, with the outer rings representing faster pitches; the angle of the spin is shown as degrees of the circle. (Here we are using PITCHf/x classification; not only does this mis-classify many two-seam fastballs as four-seams, it omits the cutter altogether, merging it in with the changeup.)

Porcello Latest Start IMG 2

The two- and four-seam fastballs are thrown at similar velocities in each game, with the four-seam fastball being close to a vertical backspin and the two-seam version having its spin tilted more to the side. (Since backspin causes a pitch to rise relative to the path it would take in the absence of spin, the fact that the two-seam has less pure backspin and more sidespin causes it to sink relative to the four-seam fastball, and to have more horizontal movement. Note that the two-seam still has considerable backspin and does actually rise relative to its hypothetical spin-free path; it is only a “sinker” relative to the four-seam pitch.)

In Porcello’s August 26 start, the two-seam fastball is not unusual in its spin direction or velocity. One interesting point, though, is that the four-seam fastball is actually showing more tilt in its spin angle; the four- and two-seam versions merge into each other in this chart, while in most previous games the four-seam was much closer to having a nearly 180 degree spin direction.

Note, by the way, how bad PITCHf/x is at identifying which of Porcello’s pitches are two-seam and which are four-seam. In many of the games, it is obvious to the eye that up to half of the pitches classified as “FF” are actually two-seamers. Any site that relies on PITCHf/x for classification (which I believe is all of them except will have significantly incorrect numbers for two- and four-seam usage.

Spin is reflected in the vertical and horizontal movement of the pitches. Here, rather than rely on PITCHf/x, pitches have been grouped with circles that roughly outline where they usually fall, as a visual guide. To keep the focus on the fastballs, sliders and changeups have been omitted:

Porcello Latest Start IMG 3


Again, August 26 is somewhat of an outlier for both two- and four-seam fastballs. The four-seam has fairly typical vertical movement, but has significantly more horizontal movement than usual. Conversely, the two-seam has more vertical movement than usual, but it has typical horizontal movement. The usual separation between the two pitch clusters is almost completely lost.

Remember that since the sinker has backspin, its vertical movement means rise relative to the gravity-only path. That means that large vertical movement, like this, makes the pitch less of a sinker, not more. In other words, although Porcello’s four-seam fastball had exceptional horizontal movement in that game, his sinker was not particularly sinking.

If we look at Porcello’s pitch location and outcomes, another pattern appears, especially in his pitches to right-handed batters:

Porcello Latest Start IMG 4

Note the “doughnut hole” in the RHB chart; while almost all Porcello’s pitches were in, or very close to, the strike zone, none were in the heart of the strike zone. To lefties, he filled in the bottom third of the strike zone with two-seam fastballs.

The last time we looked at Porcello’s pitches, we concluded that the quality of his pitches had not changed much from his much more successful 2014, but that he simply wasn’t locating his fastballs especially his four-seam fastballs well. As John Farrell said (as quoted by Timothy Britton), “The damage is coming on mislocated four-seam fastballs, and that’s an area that’s being addressed continually with the side work.”

Here once again, there is little evidence that his pitch quality per se has changed. This game shows that Porcello has a pair of good fastballs, with excellent movement, and that when he can locate those fastballs he can get most major-league batters out.

Ian York has written about Koji Uehara, an impressive start by Eduardo Rodriguez, Joe Kelly’s approach in certain counts, the effect of better bullpens on offensive strategy, a look at how Blake Swihart has been doing this season, Matt Barnes’s first start, and a look at the much improved Jackie Bradley Jr.

Follow Ian on Twitter @iayork.

Check out Rick Rowand’s suggestion for Boston’s new GM, the final installment of Jimmy Wulf’s SaberSeminar Recap and Pete Hodges’s look at possible September call ups.