Tales of the cutter: an analysis of Joakim Soria

I don’t know any other major league pitcher who relies on his cut fastball to nearly the same extent as Mariano Rivera, but there are many pitchers who use a cutter to some degree. Most of them, like Josh Beckett, merely put a little “cut” on a fastball now and then, and it’s debatable whether to classify it as a separate pitch in their repertoire. Some of them, like Greg Maddux, throw both a cut fastball and another fastball as fairly distinct pitches. A few others, like our subject today, throw a single type of fastball that moves more like a cutter than it does like a traditional four-seamer. Do we also label this kind of a pitch a cut fastball?
The cutter is second only, perhaps, to the slider in the flexibility of its definition. Almost every starting pitcher is said to throw a cutter by an obscure report somewhere. I’ve learned to discount these notional references, but I pay a lot more attention when the pitcher himself or his catcher says he threw a cutter.
Which brings us to Joakim Soria, closer for the Kansas City Royals. The Royals picked him up from the San Diego Padres in the Rule 5 draft last winter, and what a find that was! He had been pitching well in the Mexican League, and showed his stuff for the Royals last year when the closer of plan, Octavio Dotel, was first injured and later traded. Soria appeared in 62 games, pitched 69 innings, allowing 46 hits, 19 walks, and only three home runs, while racking up 75 strikeouts to go with 17 saves and 2.48 ERA.
What pitches does Joakim Soria throw? His catcher John Buck reports:

“It’s hard to pick him up. His ball has a natural cut to it. Not as much as [Rafael] Soriano but it does have a cut to it. That’s just his natural fastball,” Buck said.
“He has a great slider and curveball and can throw his change-up on any count. You have to kind of speed up your bat to get the head up to hit the cutter and, all of a sudden, he throws a changeup and it makes it difficult — sitting in-between those two is a tough place to be as a hitter.”

So his catcher calls his fastball a cutter. Let’s take a look at the data we have from PITCHf/x for the 2007 season, covering 477 pitches for Joakim Soria. I’ll begin with a graph of pitch speed versus the angle at which the spin on the ball is deflecting the pitch.

Soria Pitch Speed vs. Spin Force Angle
Soria has a fastball with a lot of cut that runs 89-94 mph. The cut fastball is his bread-and-butter pitch; he uses it for 69% of his pitches to lefties and 78% of his pitches to righties.
He has a changeup with a lot of lateral action that he throws 80-84 mph. He uses the changeup almost exclusively to lefties, making up 19% of his pitches to them.
As his off-speed pitch to righties, Soria uses a slider with a big break that runs 76-81 mph. The slider makes up 11% of his pitches to right-handed hitters.
Rounding out his repertoire is a slow curveball that Soria throws 66-71 mph. The curveball makes up 10% of his pitches, and he uses it equally to lefties and righties.
Let’s look at how these pitches move from the hitter’s perspective.

Soria Vertical vs. Horizontal Pitch Movement
All of Soria’s pitches have good movement. His fastball has”cut” to it, and his changeup has good lateral and vertical movement when compared to his fastball. His slider looks like most pitchers’ curveballs, and his curveball is a slow ball with a lot of drop.
Next, let’s look at what pitches Soria throws in each ball-strike count.

Count Cutter Changeup Slider Curveball Total
0-0 114 6 6 0 126
0-1 40 14 12 2 68
0-2 19 3 2 16 40
1-0 39 3 1 0 43
1-1 35 3 5 1 44
1-2 19 2 1 20 42
2-0 14 0 0 0 14
2-1 24 1 0 0 25
2-2 22 7 5 10 44
3-0 0 0 0 0 0
3-1 3 1 0 0 4
3-2 25 2 0 0 27
Ahead 78 19 15 38 150
Even 171 16 16 11 214
Behind 105 7 1 0 113
0 strikes 167 9 7 0 183
1 strike 102 19 17 3 141
2 strikes 85 14 8 46 153
Ball 0-1 266 31 27 39 363
Ball 2-3 88 11 5 10 114
Total 354 42 32 49 477

And here’s the same information presented graphically:
Soria Pitch Mix by Count
We can see that until he gets a strike, Soria uses almost only the cut fastball, and when he gets two strikes, he brings out the curveball pretty often, except in a 3-2 count, where he sticks with the cutter. This would imply that the curveball is his strikeout pitch and that he has trouble getting strikes with his off-speed pitches.
As a second opinion, you can look at what Josh Kalk’s algorithm spit out for Joakim Soria. Josh also has release point data there if you are interested in that.
Finally, let’s examine where Soria throws his pitches and what results he gets.

Cutter 34 44 30 10 20 8 12 0.286 0.429 77% 85%
Changeup 15 3 11 5 5 2 3 0.286 0.429 63% 78%
Slider 2 0 0 0 0 0 0 0%
Curveball 10 1 1 10 1 0 0 0.000 0.000 57% 17%
Cutter 60 43 54 18 24 9 15 0.273 0.455 71% 83%
Changeup 0 1 0 0 0 0 0 100%
Slider 14 3 0 5 6 2 5 0.250 0.625 53% 62%
Curveball 10 5 2 7 2 0 0 0.000 0.000 62% 36%

CS=called strike, SS=swinging strike, IPO=in play (out), IPNO=in play (no out), TB=total bases, BABIP=batting average on balls in play (including home runs), SLGBIP=slugging average on balls in play (including home runs). For Strk% all pitches other than balls are counted as strikes. Con% = (Foul+IPO+IPNO)/(Foul+IPO+IPNO+SS).

Our earlier conclusions seem to hold up.
Here are Soria’s results for the cut fastball.

Soria Cutter Location
To lefties, Soria seems willing to pound the zone with the cutter, and his results indicate that strategy works. Against righties, he works more up and away. He misses the zone a little more often, and he generates more foul balls, but his results are still good.
Moving on, let’s see the results for the changeup and slider:

Soria Changeup Location

Soria Slider Location
As I mentioned earlier, Soria uses the changeup to lefties and the slider to righties. In both cases, he likes to throw down and away. It looks like he has trouble throwing the slider consistently for strikes.
Last, but not least, the curveball.

Soria Curveball Location
Soria gets a lot of swinging strikes in the zone to both lefties and righties. The only difference appears to be when he misses–down and away to righties, and up and away or down and in to lefties.
Since I mentioned earlier that the curveball looked like Soria’s strikeout pitch, let’s check on that. We have PITCHf/x data for 40 of his 75 strikeouts. For those 40 K’s, 23 of them were on the curveball, 9 on the cutter, 4 on the changeup, and 3 on the slider.
I hope you enjoyed the analysis of one of my favorite players from my favorite team. My work’s had a bit of an “East Coast bias” lately, which feels a bit odd to me. I don’t expect to continue solely in that vein. If nothing else, you should see a Royal popping up in this space now and then.


4 Responses to Tales of the cutter: an analysis of Joakim Soria

  1. dan says:

    I haven’t seen it elsewhere, so can you give a general explanation of the polar graph which shows speed vs. spin deflection angle, as well as how to read it?

  2. Mike Fast says:

    Pitch speed is measured 50 feet from home plate and is shown on the radius of the polar graph.
    The spin deflection angle is the angle at which the ball is breaking due to spin, i.e., the angle of the Magnus force. For an overhand fastball with pure backspin, the Magnus force points up (spin deflection angle = 90 degrees). For an overhand curveball with pure topspin, the Magnus force points down (spin deflection angle = 270 degrees).
    So the angle on the graph shows which way the ball will move due to aerodynamic effects (spin), and the farther out on the graph, the faster the pitch was thrown.
    I didn’t present any information on spin rate in this article. The faster the ball is spinning, the more it will break, but I didn’t have room for every graph in this article, so I left that out.

  3. jinaz says:

    A less prominent player who apparently gets a lot of mileage out of his cutter is the Reds’ Jared Burton. He’s not as extreme as Rivera, but I thought I’d point him out as a fellow Central division player (albeit in the NL). Here’s Josh Kalk’s player card on him.

  4. Guillermo says:

    Excellent work.

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