Josh Donaldson vs. a Curveball

This is the kinda-sorta third installment in my Swing Grading Series. It is also the kinda-sorta lower body portion of my Front Side Mechanics piece. So I kinda-sorta get a 3-for-1. Enjoy!

The last couple weeks we looked at how hitters make adjustment to their swings to hit the ball to all fields and to cover the plate. But what about adjusting for pitch speeds? We will discuss this topic today.

First, we are talking about swing adjustments. Sometime hitters sit curveball and time it perfectly and kill it. But for this article, we are going to be discussing swing adjustments when a hitter sees something he wasn't expecting. For illustration purposes, we will look at handling the curveball.

Let's look at a couple of swings. The first is a 93 mph fastball Josh Donaldson hits for a home run. We have a timer starting when the pitcher releases the ball and stops when Donaldson makes contact.

Now here is another pitch. This one is a 78 mph curveball Donaldson hits for a home run. Again we have a timer measuring the time-of-arrival of the pitch.

Not surprisingly, the fastball has a shorter time-of-arrival than the curveball (2 frames or roughly .07 seconds). So the hitter is going to have to find a way to adjust to the difference in pitch speed. How does he do it? Let's look at some options. The hitter can

1. Wait longer to start the swing, then complete the swing in the same time as a fastball swing.
2. Start the swing at the same time, but stride differently or slower, then swing the bat in the same time as a fastball swing.
3. Start the swing at the same time, stride the same speed/time, pause the swing, then swing the bat in the same time as a fastball swing.
4. Or start the swing at the same time, stride the same way/time, then swing the bat slower than a fastball swing.

Got your answer? I should have put a poll in here. Oh well. Let's see what the answer is!

Below I have the two swings of Donaldson synced at pitch release. Study it carefully.

Here are a few things to point out. First, there is a lot of movement going on before the release of the pitch. And the movement is consistent for both pitch types. In the initial portion of the swing, Donaldson is timing the pitcher, not the pitch. By the time the ball is released he is in the same position in both swings. So if you said Donaldson waits longer to start the swing (Option 1), sorry, you are incorrect.

Second, a few frames after the release of the ball (as Donaldson is putting his front foot down) he is in the same position for both swings. His stride (so far) is exactly the same. So Option 2 is out as well.

Let's move to the side view to see what happens next. See how on the fastball Donaldson transitions from stride to bat-swing instantly. As soon as his front foot plants his swing is underway (in fact, we used the front foot planting as our starting point for swing time).

But now on the side view of the curveball swing, we see something different. Instead of transitioning into the bat-swing instantly, Donaldson "pauses" a little by continuing his forward movement into his front leg.

Donaldson's front leg buys him some time to let the pitch get to him. But he isn't stopping his energy. His momentum continues as he allows his front leg to buffer his swing. For a swing nerd like me, this is really nice to watch.

Once Donaldson starts the bat-swing, we see the same swing time as the fastball swing - 8 frames (@60 fps) from initiation. So if you said Option 4, sorry, you are incorrect. The correct option is Option 3 (when in doubt, always go with the 3^rd or ‘C' choice).

If we think things over a bit, we see Option 3 really makes the most sense. We saw that Donaldson does a lot of swing movement before the pitch is even released. This is simply because there isn't time to read fastball or curveball and then swing. Option 1 just simply isn't possible. Option 2 sounds good, but as we saw Donaldson actually starts moving forward before the ball is released. So for him to slow down or alter his stride once he recognizes off-speed would be a pretty difficult task. Plus he would lose all the good movements he has done up to this point. Option 4 isn't very good because the bat-swing would be slower and we would have a harder time making solid contact and hitting the ball with authority. Option 3 is really the best choice.

As mentioned before, this "pause" is really all in the front leg. The key is how hitters finish their stride. Look at the finish of the stride on both swings. At this point, you can't tell if Donaldson is going to launch the bat or not. His front leg is holding his lower body in, keeping it from starting the swing too early. If he needs to delay his swing, Donaldson will get into the front leg. If he needs to swing instantly on a fastball, the front leg will open and start the swing. Simple. Donaldson isn't "keeping his weight back" to allow him to adjust to offspeed pitches.

Of course not everyone does this as well as Donaldson (who hit .319 and SLG'd .681 against curveballs in 2013). I saw the other day former A's prospect Brett Wallace was DFA'd by the Astros. It got me thinking about his swing and the huge strike-out totals. In his swing, Wallace does "keep his weight back" by tipping his upper body and gets his front leg far ahead of his hips. This causes problems in the swing. See how early in the swing Wallace (basically at footplant, compare to Donaldson above) has allowed his leg to get extended and open his front hip. Wallace's body tip keeps the weight off the front leg. His front knee can't control the stride very well. Wallace's swing doesn't have a mechanism to delay for off-speed pitches.

Below is a couple more swings shown as he is setting the front foot down. We see the front leg too far in front of the body and nearly locked out.

When we look at Wallace's ability to hit pitches, we see he hits the faster stuff pretty OK. But on the curveball (the pitch with the biggest speed change vs. the fastball) he really struggles.

Pitch Type	Count	AB	K	BB	HBP	1B	2B	3B	HR	BAA	SLG	ISO	BABIP
Fourseam	1383	278	74	29	9	44	15	1	10	0.252	0.421	0.169	0.309
Sinker	898	189	33	20	3	36	13	1	5	0.291	0.450	0.159	0.331
Change	453	121	41	4	0	19	4	0	6	0.240	0.422	0.182	0.311
Slider	522	146	76	6	2	15	8	0	4	0.185	0.322	0.137	0.349
Curve	446	109	61	0	2	13	3	0	2	0.165	0.248	0.083	0.348
Cutter	304	55	9	6	4	11	3	0	1	0.273	0.382	0.109	0.311
Split	115	30	9	2	0	6	1	1	1	0.300	0.500	0.200	0.400

Some hitters do the opposite of Wallace with too much inward turn of the front leg. With too much inward turn, the front leg becomes a hard brake of the stride instead of soft, controlled landing. See how in 2013 (right swing) Yoenis Cespedes just has so much more inward turn of the front leg than in 2012 (left swing) at the same point in his swing (swings synced at contact on two fastballs). His front knee can't accept the stride as well, and won't allow him to delay his bat-swing.

The numbers bear this out as well. See how in 2012 Cespedes was actually a decent curveball hitter. But in 2013 those numbers really dropped. (For more about Cespedes' change in front leg function from 2012 to 2013 read this).

Pitch Type	Count	AB	K	BB	HBP	1B	2B	3B	HR	BAA	SLG	ISO	BABIP
Curve (2012)	184	58	19	5	0	7	2	0	4	0.224	0.466	0.241	0.257
Curve (2013)	214	50	14	0	0	6	0	1	0	0.140	0.180	0.040	0.194

So the next time you hear the announcer say "He didn't keep his weight back against the curveball," keep in mind it really may have been the front leg function that got him a ticket back to the dugout.

(For a video on Troy Tulowitzki making the same swing adjustment as Donaldson, watch this.)