All about Ben Sheets

The first time I heard of Ben Sheets was in 2000, when he anchored the U.S. Olympic team in Sydney, pitching a three-hitter in the Gold Medal match against Cuba, keying a 4-0 victory. From then on, Sheets, the 10th overall pick in the 1999 draft, was permanently on my radar.

He was called up the next year, and though he struggled somewhat, ended the season with an 11-10 record and a 4.76 ERA—not bad for a 22-year-old. He tired as the season wore on, and his ERA ballooned from 3.59 before the All-Star break to 7.06 after. Certainly, there was still a lot of hope.

That hope, however, did not get fulfilled for three more seasons, until Sheets properly broke out in 2004. That year, Sheets pitched 237 innings, struck out 264 batters while walking just 32, and posted a sterling 2.70 ERA. It looked like he’d finally put it all together.

Unfortunately, that’s also when Sheets’ injury problems started. After pitching well over 200 innings in 2002, 2003 and 2004, Sheets has not approached that mark since. In 2005, he was sidelined with an inner ear infection; in 2006, it was shoulder tendinitis; and in 2007, it was a multitude of body parts.

When healthy, however, Sheets has been very good. Over 404 innings in the past three seasons, Sheets has struck out 363 batters, walked 73, allowed 45 home runs, and posted a 3.63 ERA. Last season, however, his otherworldly walk ratio more than doubled (though it was still very good), his strikeout rate fell, and Sheets’ fielding independent ERA (FIP) ballooned to 4.10.

Amidst questions about his ability to stay healthy, there were suddenly questions about just how good a pitcher Sheets is at this point. In his first four starts this season, Sheets seemed to answer the latter concerns definitely. In 28 innings, Sheets went 3-0 with 24 strikeouts, four walks and just one home run allowed, all adding up to a 0.96 ERA.

Unfortunately, the former questions have reared their ugly head. Sheets complained of tightness in his triceps after his fourth start, and so the Brewers skipped his next turn in the rotation. He came back Tuesday, but walked seven hitters while striking out just two in five painful innings. Sheets attributed the poor outing to rustiness, but that certainly is not an encouraging sign.

So today, we’ll take a careful look at the pitcher that is Ben Sheets. We’ll look at what PITCHf/x data can tell us about him, but we won’t stop there. I’ve enlisted the help of Dan Loeterman, a student of mechanics, who will give us a detailed breakdown of Sheets’ mechanics, and the help of our own injury expert Chris Neault to analyze Sheets’ long history injury and tell us what it might mean for his future.

There’s a lot of PITCHf/x analysis being done online these days, as well as a lot of mechanics stuff, and some injury analysis too, but I think the three are much more powerful descriptive tools when combined than when they are separate, so I’ll try to write this kind of an article occasionally from now on. Let me know what you think about the format; my e-mail is available at the bottom of the article.

What does he throw?

(Note: We’re going to focus on data from Sheets’ first four starts in 2008, since he did feel out of sorts on Tuesday.)

The amazing thing about Sheets is that his dominance rests on basically just two pitches, his fastball and his curve. Sheets throws his fastball 61 percent of the time and his curveball makes up 35 percent of his pitches; the other four percent are changeups. Sheets’ pitches are really easy to identify if we plot vertical movement versus pitch speed:

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You can see that Sheets’ pitches form three distinct clusters: a fastball that averages about 92 mph and 11.3 inches of vertical movement (compared to a theoretical spin-less pitch thrown at the same speed—obviously, Sheets’ fastball does not literally move up); a changeup that averages about 85 mph and 6.6 inches of vertical movement; and a curveball that is thrown at 79 mph and has 4.8 inches of drop to it.

Already, we start to see some of the reasons for Sheets’ dominance. His fastball is very much fast, especially considering that pitch speeds are considerably slower in the cold month of April (especially in Milwaukee), and it has about two-and-a-half more inches of rise to it than your average fastball. There are going to be lot of swings-and-misses on that one.

Sheets’ curveball is still nastier—t comes in a few miles per hour faster than your average curve, but somehow it drops an inch and a half more. Ten percent of Sheets’ curveballs result in swinging strikes, while 27 percent of the time batters are too confounded to even swing at a curve in the strike zone, versus a league average of 19 percent.

Let’s also look at the customary plot of vertical versus horizontal movement:

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As is normal, Sheets’ fastballs move in on right-handed batters (and away from lefties), while his curveballs move away from right-handed hitters. What’s interesting, however, is that Sheets’ fastball has a lot less horizontal movement than an average fastball, more than two-and-a-half inches less. For those worried about data quality issues, Josh Kalk’s corrected data from 2007 shows much the same thing.

Of course, Sheets makes up for that lack of boring action with extra vertical movement and pure speed. In fact, I wonder if that is a conscious tradeoff.

Anyway, as good as it is, Sheets’ pure brilliance does not come from the quality of his stuff, but its accuracy. Sheets throws all his pitches for strikes: Just 34 percent of his fastballs are called balls, only 31 percent of his curveballs (versus a league average of 40 percent!), and only 27 percent of his changeups (though the sample size here is tiny). In total, two-thirds of Sheets’ pitches are strikes, compared to an average of around 62 percent.

To summarize the total picture here, we can see that Sheets is still a very good pitcher. His fastball and curveball are both very good pitches, and his accuracy means that hitters can’t lay off those pitches and hope Sheets is wild when they face him. In the next two sections, we’ll try to answer two questions:
(1) Mechanically, what does Sheets do well and what does he do poorly, and
(2) Does his propensity for injury mean that we’ll never see Sheets’ great pitching for any prolonged period of time?

Sheets’ Mechanics

by Dan Loeterman

Ben Sheets does an excellent job of keeping his pitching motion tight and compact, and when healthy he’s been one of the majors’ best pitchers. He has good rhythm, breaking his hands as he lowers his leg from the kick, and his weight isn’t too far forward on his step.

Despite the high leg kick, Sheets’ lower body is not especially active (discussed below), though he compensates by bringing the ball in a wide circle—the wider the circle going into release point, the more power—and slingshotting it toward home plate. He pushes off well with his back leg and has a strong follow-through with that back leg, indicating a good transfer of power from the lower body to the arm.

But Sheets doesn’t use the rest of his body to generate nearly as much power as he could, and he doesn’t lead toward home plate well with his front shoulder. To demonstrate this, I’ve compared Sheets’ delivery to Josh Beckett’s at a few crucial points.

The Kick

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(Note: In all these pictures, Sheets is on the left, Beckett on the right.)

After a pitcher kicks his leg, he is supposed to bring the foot right back to the ground and glide along the ground, keeping the weight even between the front and back feet until the last moment, when he opens his hips and generates power using his lower body and core.

This comparison shows each pitcher as his leg is on the way down from the kick. Sheets’ leg is completely straight and pointed toward third base as he lowers his leg from the kick. Instead of leading with his knee and preparing to open up his hips in a rush of torque and power, he’s preparing to lazily swing his foot around instead. This delivery gives him about as much power as if he was pitching from the slide step, and he has to generate all the power from his back leg.

Beckett, on the other hand, has kept his knee bent and is preparing to swing the knee open.

This image shows how exaggerated that kick toward third base is:

image

The Step

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This image is taken from the moment each player’s front foot hits the mound. Beckett is leading with his shoulder toward home plate, and is keeping his shoulder closed in until the last second, as a good hitter would. Even as he rotates his hips, his momentum is forward. His body is completely perpendicular to the ground, and he’s preparing to open up that front shoulder and use his core and upper body strength to fling the ball forward.

Sheets, by contrast, is leaning way off toward first base; his momentum isn’t forward, but to the side. His shoulder has already opened up and is pointing to the left of home plate. At this point, he’ll rely more on arm strength to deliver the pitch.

Arm Slot

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With these pictures, we can compare the pitchers’ arm slot. A lot has been made of Sheets’ arm slot, and he admitted during spring training this year that command of his arm slot comes and goes.

The trick with arm slot is to get the right combination of torque, from side to side, and moment forward. Come too far over the top and your body won’t be able to give you enough torque and power; bring your arm too low and the power will be in the wrong direction entirely, and you’ll put too much stress on your arm.

A “three-quarters” arm angle, where the pitcher roughly makes an L with his arm as the point of release, is generally believed to be the best compromise. To understand why that arm angle provides more power, plant your feet on a solid surface and hold your arms straight out from your body to each side, so they’re parallel to the floor. Ball your right arm into a fist. Now rotate your upper body to the left, and then all the way back to the right. Notice how much torque is built up in your right fist. Now hold your arms straight up like a referee signaling a touchdown, ball your right fist, and repeat the exercise. Notice how little torque you’ve build up. By having a lower arm angle, you can transmit the side to side energy of your shoulders and hips into velocity.

But instead of forming an L, Sheets’ arm slot is too high. And while Beckett’s shoulders are square toward home plate—he’s waiting long enough to open up his body until the exact right moment—Sheets’ shoulders are square to the left of home plate, just as his front shoulder was pointing in that direction. Falling off to the side may be one reason why Sheets has such a tough time finding the right arm slot; because he is leaning so far to the left side, it’s almost impossible for him to get the ideal three-quarters slot by lowering his right arm. His arm is dragged up by his body, as if to compensate.

(One advantage of a more over-the-top arm slot like Sheets’ is the devastating 12-6 action he gets on his curveball.)

Follow through

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Finally, we have each pitcher’s follow through. Once again, you can see that Sheets is leaning way off toward first base, while Beckett follows through toward home plate.

Obviously, Sheets has proven to be a very good pitcher when healthy, but these aspects of his mechanics often work against him.

Why can’t he stay healthy?

by Chris Neault

Believe it or not, Sheets was not always labeled “injury-prone.” In fact, from 2001 to 2004, he stayed quite healthy, and accumulated a heavy workload, logging 151.1, 216.2, 220.2, and 237.0 innings pitched in each of those years, respectively.

He was able to start 34 games for the Brewers in 2002, 2003, and 2004. After an absolutely fantastic 2004 season that saw Sheets tally 264 strikeouts versus only 32 walks, while allowing only 201 hits in 237 innings, it looked as though Sheets was on his way to being a household name amongst the greats of the game.

Then the injuries began to pile up for the three-time All-Star:

  • In 2005, he sustained what was termed a “viral infection” of the inner ear, and missed 30 games due to dizziness and altered balance.
  • A torn latissimus dorsi muscle in his right shoulder occurred in late August and ended his season.
  • In the offseason, he had a microdiscectomy back surgery to correct a herniated disc in his lumbar spine (low back). While this is considered to be a minor back surgery, it should be noted that no back surgery is “minor.” Having any spine procedure as a 27-year-old is somewhat concerning, and leads me to wonder how his overall core conditioning is.
  • The 2006 season saw Sheets begin the year on the DL due to a posterior shoulder strain.
  • Tendinitis of the right shoulder landed him back on the DL in early May. He spent a great deal of time on the DL with this injury—a span of 72 games passed before he returned to action.
  • A torn tendon in his right middle finger sidetracked his 2007 campaign; he was sent to the DL in July and missed a course of 40 games.
  • After returning for a few starts, a minor hamstring strain was enough for him to miss the final eight games of the regular season.
  • He has also dealt with an array of minor injuries that did not require much, if any, missed time (right pectoral strain, left groin strain).

The latest injury for Sheets has been coined, “right triceps tightness,” but it might as well include the rotator cuff. In my clinical experience, I have seen very few baseball pitchers present with a pure, isolated “triceps strain”—rather, there is almost always an involvement of the rotator cuff muscles in what is called the “Quadrangular Space.”

Why do these injuries continue to mount for Sheets? The culprit appears to be his high arm slot. Although it’s partly responsible for the large 12-6 curveball, it’s also responsible for taxing the rotator cuff to the max. As a rule of thumb, the higher the arm slot, the harder the rotator cuff and biceps must work to stabilize the head of the humerus. This places stress on the rotator cuff interval, which includes ligaments in the front of the shoulder that also add stability. Let’s talk about this in a little more detail.

Sheets places a lot of horizontal abduction on his shoulder when he brings the ball behind him at the beginning of his throwing sequence—prior to the cocking phase. He brings his pitching arm far behind his trunk, and basically points his elbow and forearm beyond second base (to the right side of the infield). This is the beginning of the “wide circle” that Dan was talking about. This motion places stress on the anterior shoulder structures such as the anterior joint capsule, coracohumeral ligament, pectoralis major, biceps, and labrum.

When the arm reaches this position, the shoulder is internally rotated, and is decelerated passively by the anterior shoulder structures and eccentrically by the posterior rotator cuff musculature. The small muscles of the posterior rotator cuff then need to contract to begin the external rotation phase, in an attempt to bring the shoulder into the cocking phase.

Keep in mind, these muscles are quite small, and are not “power” muscles. The rotator cuff is a group of deep stabilizers, responsible for fine-tuning motion and controlling the head of the humerus in the socket.

The shoulder is still behind his body in horizontal abduction at this point. He does not use his lower body effectively, as Dan pointed out, and incorporates a heavy trunk lean towards first base, which in turn helps bring his pitching arm up into his high arm slot.

Just before this happens, as the shoulder is reaching the maximum amount of external rotation, the internal rotators of the shoulder powerfully contract to decelerate the shoulder. This would include the subscapularis, pectoralis major, teres major, and latissimus dorsi. These muscles then contract forcefully to help bring the pitching arm forward toward home plate.

Following release, the posterior rotator cuff muscles decelerate the pitching arm once again, in addition to the latissimus dorsi.

That is a lot of work for the shoulder to endure—especially in the case of Sheets, who displays a tremendous range of motion at his shoulder during his whole pitching motion. Plain and simple, he has a lot of motion to control with his rotator cuff, which leads to his frequent injuries.

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