The top 10 pitches by A's starters per whiff percentage

Whiffs are looked at as a key to a pitcher's "stuff"; more whiffs obviously indicates a better pitcher. Garnering whiffs is also big as your defense can't screw up on balls not in play, save stolen bases and dropped thirds. This is extra important when you have noodle arms and concrete gloves sprinkled around the diamond. The A's should be decent defensively next year, but whiffs are still imperative.

Per Brooks Baseball, these are the top 10 whiff inducing pitches by A's starters from the 2015 season. These are taken from a sometimes tiny sample and don't necessarily indicate the best pitches, just the pitches you're most likely to see a grown man swing a piece of lumber through the air without making contact with a ball.

10: Kendall Graveman's changeup, 11.36%

Graveman is often thought of as an innings eater type or back of the rotation guy, and it's true, with a K% hovering around the 15% level, he's not exactly an ace. That said, Graveman's has shown some downright good stuff. His changeup induced swings and misses 11.36% of the time and was a pitch Graveman used in all counts. It wasn't great as a putaway pitch, inducing only 5 strikeouts in the 51 times an at bat ended wit his changeup but he utilized the change to get ahead of hitters. The development of that pitch should be a key in his 2016 success.

9. Rich Hill's changeup, 11.43%

If you're expecting to see Rich Hill's curveball on this list, prepare to be disappointed. That doesn't mean it's not an absolutely beautiful pitch nor a great one, it just means hitters aren't swinging and missing, likely cause they're too mesmerized to even swing. The curveball still induced 13 strikeouts in 41 at bats, meaning he's still very effective with it.

But I'm here to talk about the changeup, a pitch Hill used sparingly in 2015 and only against RHH. The rareness of the pitch (10% of the time against RHH) seemed to do Hill well, inducing groundballs 75% of the time it was actually put in play and inducing a swing and miss 26% of the time hitters actually swung at it. We'll discuss Hill's fastball later on and the success of both pitches are intertwined. Hill likes to throw the changeup while ahead in the count to righties, a situation in which he also favors the fastball.

Granted, were dealing with a small size within a small size but the change is a seldom used weapon that should help Hill against righties. You can see the change 26 seconds into the video below.

For more on Hill, be sure to check out JosephTDeClercq's piece on the A's new lefty.

8. Jesse Hahn's curveball, 11.45%

Hahn makes his lone appearance on this list with what is undoubtedly his best pitch, and a joy to watch. The curve actually wasn't that fruitful for Hahn in 2015 per FanGraphs ratings but Hahn's season was cut short just as he was hitting his stride. Hahn uses his curve almost exclusively when ahead in the count and that has resulted in a 29% K rate in at bats ending with the curve.  I imagine Hahn's ability to take the next step will depend on his ability to use the curve more dynamically in different counts.

7. Kendall Graveman's cutter, 13.45%

When Graveman came over from the Jays, the A's gushed about his cutter. It took a little while to materialize, but the pitch eventually showed its potential. Hitters swung and missed at the cutter 28% of the time they swung the bat. But as anyone who watched Graveman with any regularity last year will tell you, the consistency is sorely lacking. The numbers back it up, as Graveman gave up 8 homeruns on the cutter in spite of the high whiff rate. Those particular cutters presumably didn't cut at all, and an obvious path to success for Graveman is for his cutters to actually, you know, cut. The disparity between the whiff numbers and the homerun numbers on the cutter give a good indication why the A's were so high on Graveman but also explain why he was so underwhelming at times in 2015. Fix your cutter, Kendall.

6. Aaron Brooks slider, 14.37%

Bet you didn't expect to see Aaron Brooks on this list! Brooks has some major talent for a guy who couldn't get anyone out for like a month last year, but there's no denying that some of his stuff is pretty nasty. Part of it may be SSS, but it should give you reason for hope going forward.

Brooks uses his slider almost exclusively against righties which makes sense, as it'd be a big threat to hit batters if he threw it to lefties. In spite of the high whiff rate, it's not all roses with the slider as Brooks gave up 15 hits in 33 at bats, including a dinger. It's clearly got a bit of Jekyll and Hyde tendencies like Graveman's cutter, but also has potential. Wondering why the slider got such bad results? It's probably location based. As you'll see in the chart below, too many sliders end up in the heart of the plate, likely signifying a big juicy hanger. You'll see an example of a good slider at 22 seconds into the video below. If Brooks can find consistency with the movement of his slider, he'll hit his spots and get good results.

5. Sonny Gray's cutter, 14.67%

It's a little unfair to put Sonny's cutter on the list, as he only threw it 2% of the time. But I didn't set any sample size rules so here we are. Plus, any excuse to talk Sonny is a good excuse. The diminutive righty is undoubtedly the best pitcher in Oakland, and the fact that a pitch he doesn't even use garners such impressive numbers tells you just how talented he is.

I had originally written that I wasn't sure if Sonny was really throwing a cutter or if it was a PitchF/X mischaracterization. The always insightful danmerqury helped clarify in the comments below that Sonny is in fact throwing a cutter. We can be sure that Sonny is even more awesome than we thought. Big thanks for the help, Dan!

Fun times with classification models, Brooks Baseball, and Sonny’s cutter: Brooks Baseball automates most of their pitch identification using some kind of machine learning classification model with some human assistance and review here and there (I’m guessing on this, but I’m pretty sure that’s how they do it—100% manual classification would be so much work). Sonny had never really used a cutter before 2014, so Brooks’ model was going into his classification process knowing that he only threw two fastballs, a change, a slider, and a curve. Midway through 2014, though, Sonny started throwing cutters every so often. Brooks’ model would treat any pitches that looked like cutters as four-seam fastballs that had a little more glove-side movement than usual or sliders with a little too much positive vertical movement. But to anyone watching the PITCHf/x or Trackman numbers, it was pretty obvious that he had started experimenting with an actual cutter, and these weren’t weird blips.

And then at some point towards the end of 2014, all of a sudden, Brooks’ model decided that there was enough evidence to create a new classification pitch group. The model flipped the switch, and now it knows that Sonny throws cutters. Pretty cool to see that play out in real time over the course of several months.

I know there's some worry that Sonny has reached his peak, but the fact that he's just tinkering around with new pitches and seeing big success with them tells you he's got room to grow. It's hard to put too much stock in the tiny sample so far, but the swings and misses are a good sign. Like his fastball, the command of the cutter isn't great (it's thrown for a ball 40% of the time) but it's new and it will likely get better.

4. Chris Bassitt's curveball, 15.12%

We've looked at Bassitt in depth already, and while his curveball was graded out as slightly below average per FanGraphs, it's another example of a pitch with tremendous potential. When hitters actually do swing at Bassitt's curve, they miss an astounding 36% of the time. It's actually inducing swings that's the problem, as Bassitt's curve only illicits swings 29% of the time, a low for all his pitches. Why is this number so low? Bassitt's control of his curve is bad at best, and an area of improvement that can help Bassitt keep up his stellar 2015 numbers.

When at bats finish with a curveball, hitters have struck out 19 of 51 times and have yet to get an extra base hit off the deuce. If Bassitt can control that thing, look out.

3. Rich Hill's 4seam fastball, 16.19%

We've all gotten so excited over Hill and his curveball, but did you know in 2015, his fastball was rated more valuable by FanGraphs' metrics? It's a beautiful thing when a pitcher can use his fastball as such a weapon, as it's the easiest pitch to spot and can be thrown in any count. Hill has utilized the fastball to get ahead of hitters without giving up damage, setting up his other weapons.

Hitters are whiffing on over 30% of their swings on fastballs and only hitting at a .111 clip. In the 45 at bats ending with the fastball, Hill struck out an astonish 20 hitters. Pretty impressive for a guy who only throws 90-91, and even more impressive when you consider his other weapons. The movement his 4 seamer exhibited in 2015 was dominating.

Rich Hill might not be durable, but his talent is undeniable and his success in 2015 could be the start of something great.

2. Aaron Brooks changeup, 18.38%

Bet you didn't expect to see Aaron Brooks on this list! Brooks has some major talent for a guy- wait, what? Brooks is on this list twice? And at the number 2 spot? Huh.

Like a few other pitches on this list, Brooks changeup has the unfair advantage of only being used situationally, in this case most only against left handed hitters. Brooks induced 14 k's in 56 at bats with the change, but also gave up two dingers and two other extra base hits. We all know Brooks is a work in progress, but like with the aforementioned slider, Brooks has shown the stuff to succeed as a starter. Finding consistency will be key for Brooks to stick in a starting rotation.

Change is at 1:19 in the video!

1. Sonny Gray's slider, 24.41%

Was it ever really a question? Of course Sonny's gorgeous slider would top this list. Sonny uses the slider 13% of the time against lefties and 20% of the time against righties, mostly when he's ahead in the count. Opposing hitters are hitting a meager .128 against the slider and struck out 94 times in 196 at bats in 2015. That's some dominance. Want more? Hitters miss nearly 40% of the time when they do swing and if they're lucky enough to hit it in play, they usually hit it on the ground. The only negative about the pitch is hitters did hit it for out of the park 6 times, but it's still dominant. Sonny has great command of the slider, and it's rarely called a ball even though he throws it mostly ahead in the count. This is likely a testament to his fooling hitters into swinging at balls out of the zone. It is a dominant pitch, no doubt.

What makes it such a good pitch? For one, he throws is so damn hard. At 87 mph, it comes out of his hand at a similar trajectory to his fastball which makes it extremely difficult to pick up, even with the dot from the spin. With it coming out of his hand at such a low trajectory, it's easier to keep down out of the hitting zone so even poorer sliders or mistakes to location aren't easy to punish. It's just filthy.

There's a slider strikeout in the following video, but I'm not telling you where so you have to watch the whole thing. You're welcome!