Rick Porcello and Plate Discipline

Rick Porcello had an awful start on Saturday, giving up 9 ER in 2/3 of an inning. Much has been written on how he was unfortunate on some of the ground balls turning into hits that weren't hit particularly well. Rather than give my opinion on whether or not Porcello deserves another start, I’ll take this time to talk about plate discipline. FanGraphs gives plate discipline stats via Pitch f/x as shown below:

	O-Swing%	Z-Swing%	Swing%	O-Contact%	Z-Contact%	Contact%	Zone%
2012	32.4%	61.8%	46.6%	69.4%	91.7%	83.7%	48.2%
2013	31.0%	63.6%	45.1%	80.0%	95.7%	89.6%	43.1%

These stats can get confusing without the raw data. We know that Porcello has thrown 255 pitches so far this year. That's enough information to reverse-engineer these stats to show the raw numbers. I've also changed the format of the table to hopefully make it more clear:

2013	255 Total Pitches					Total
110 In Zone			145 Out Zone
40 Non-Swing	70 Swing		100 Non-Swing	45 Swing		115 Total Swing
	3 Non-Contact	67 Contact		9 Non-Contact	36 Contact	103 Total Contact

110/255 = 43.1% Zone%
70/110 = 63.6% Z-Swing%
67/70 = 95.7% Z-Contact%
115/255 = 45.1% Swing%
103/115 = 89.6% Contact%
And so on.

Below is a comparison between Porcello's 2013 and 2012 percentages. Obviously there is a small sample issue here since Porcello only has 13 innings in 2013. However, it could be interesting to see the differences:

2013	255 Total Pitches					Total
43.1% In Zone			56.9% Out Zone
36.4% Non-Swing	63.6% Swing		69.0% Non-Swing	31.0% Swing		45.1% Total Swing
	4.3% Non-Contact	95.7% Contact		20% Non-Contact	80.0% Contact	89.6% Total Contact

2012	2828 Total Pitches					Total
48.2% In Zone			51.8% Out Zone
38.2% Non-Swing	61.8% Swing		67.6% Non-Swing	32.4% Swing		46.6% Total Swing
	8.3% Non-Contact	91.7% Contact		30.6% Non-Contact	69.4% Contact	83.7% Total Contact

Difference						Total
-5.1% In Zone			5.1% Out Zone
-1.8% Non-Swing	1.8% Swing		1.4% Non-Swing	-1.4% Swing		-1.5% Total Swing
	-4% Non-Contact	4% Contact		-10.6% Non-Contact	10.6% Contact	5.9% Total Contact

The major difference is the 10.6% more contact on out of zone pitches instead of swinging and missing. This could explain why Porcello only has 3 strikeouts so far this year. Porcello was never a strikeout pitcher, but his 2.08 K/9 and 4.8% K rate are lower than the 5.46 K/9 and 13.7% K rate he put up last year. Again, I should point out the small sample size, so these numbers could certainly improve over the year.

Pitch f/x does however break these stats down to individual pitch types, and I can't pass up comparing these over the last 2 years to see if there's a particular pitch giving Porcello trouble in the early goings:

2-Seam Fastball

2013	39.2%					Total
47% In Zone			53% Out Zone
34% Non-Swing	66% Swing		64.1% Non-Swing	35.9% Swing		50% Total Swing
	0% Non-Contact	100% Contact		10.5% Non-Contact	89.5% Contact	96% Total Contact

2012	45.2%					Total
55% In Zone			45% Out Zone
40.7% Non-Swing	59.3% Swing		65.1% Non-Swing	34.9% Swing		48.3% Total Swing
	6.0% Non-Contact	94.0% Contact		23.4% Non-Contact	76.6% Contact	88.4% Total Contact

Difference	-6.0%					Total
-8.0% In Zone			8% Out Zone
-6.7% Non-Swing	6.7% Swing		-1.0% Non-Swing	1.0% Swing		1.7% Total Swing
	-6.0% Non-Contact	6.0% Contact		-12.9% Non-Contact	12.9% Contact	7.6% Total Contact

The 2-seam fastball is what Pitch f/x is calling his sinker. This is his supposed bread-and-butter pitch. He's throwing it 6% less often overall; 8% more out of the zone and hitters are making 7.6% more contact - including 12.9% more contact out of the zone. Just throwing this out there, but maybe Porcello's sinker isn't sinking enough, causing hitters to make more contact. I have nothing to back up this theory, just throwing it out there. The goal of the sinker is to make hitters hit ground balls, not make them swing and miss and hitters are hitting 7.5% more ground balls on Porcello's sinker this year than last year (67.9% in 2013, 60.4% in 2012). So this could be viewed as moving in the right direction.

4-Seam Fastball

2013	24.3%					Total
41.9% In Zone			58.1% Out Zone
30.8% Non-Swing	69.2% Swing		77.8% Non-Swing	22.2% Swing		41.9% Total Swing
	11.1% Non-Contact	88.9% Contact		25.0% Non-Contact	75.0% Contact	84.6% Total Contact

2012	21.6%					Total
52.4% In Zone			47.6% Out Zone
40.3% Non-Swing	59.7% Swing		75.6% Non-Swing	24.4% Swing		42.9% Total Swing
	7.3% Non-Contact	92.7% Contact		26.8% Non-Contact	73.2% Contact	87.4% Total Contact

Difference	2.7%					Total
-10.5% In Zone			10.5% Out Zone
-9.5% Non-Swing	9.5% Swing		2.2% Non-Swing	-2.2% Swing		-1.0% Total Swing
	3.8% Non-Contact	-3.8% Contact		-1.8% Non-Contact	1.8% Contact	-2.8% Total Contact

Porcello is throwing his 4-seam fastball 10.5% more out of the zone. Batters are also swinging at it 9.5% more often in the zone, but are swinging and missing at it 3.8% more. 2 of the 3 HR he's given up has come off the 4-seam fastball and batters are hitting .400 against it, so it hasn't been a very effective pitch so far this year.

Change Up

2013	15.7%					Total
32.5% In Zone			67.5% Out Zone
30.8% Non-Swing	69.2% Swing		48.1% Non-Swing	51.9% Swing		57.5% Total Swing
	11.1% Non-Contact	88.9% Contact		35.7% Non-Contact	64.3% Contact	73.9% Total Contact

2012	13.6%					Total
34.2% In Zone			65.8% Out Zone
25.9% Non-Swing	74.1% Swing		59.1% Non-Swing	40.9% Swing		52.2% Total Swing
	14.4% Non-Contact	85.6% Contact		34.0% Non-Contact	66.0% Contact	75.5% Total Contact

Difference	2.1%					Total
-1.7% In Zone			1.7% Out Zone
4.9% Non-Swing	-4.9% Swing		-11.0% Non-Swing	11.0% Swing		5.3% Total Swing
	-3.3% Non-Contact	3.3% Contact		1.7% Non-Contact	-1.7% Contact	-1.6% Total Contact

The big difference here is the 11.0% O-Swing rate and they are making slightly less contact on those swings. Hitters are only batting .091 against Porcello's change up, so it looks to be a pretty good pitch for him early on.

Curveball

2013	20.8%					Total
45.3% In Zone			54.7% Out Zone
50.0% Non-Swing	50.0% Swing		86.2% Non-Swing	13.8% Swing		30.2% Total Swing
	0.0% Non-Contact	100.0% Contact		0.0% Non-Contact	100.0% Contact	100.0% Total Contact

This is really surprising to see. Whenever a batter decides to swing at a curveball, they've made contact.

2012	3.2%					Total
33.3% In Zone			66.7% Out Zone
40.0% Non-Swing	60.0% Swing		75.0% Non-Swing	25.0% Swing		36.7% Total Swing
	11.1% Non-Contact	88.9% Contact		40.0% Non-Contact	60.0% Contact	75.8% Total Contact

Difference	17.6%					Total
12.0% In Zone			-12.0% Out Zone
10.0% Non-Swing	-10.0% Swing		11.2% Non-Swing	-11.2% Swing		-6.7% Total Swing
	-11.1% Non-Contact	11.1% Contact		-40.0% Non-Contact	40.0% Contact	24.2% Total Contact

Porcello is throwing his curveball 17.6% more often then he did in 2012. This is an experiment worth watching, since Porcello ditched his slider in favor of throwing more curveballs. Batters are only hitting .200 against it, though, so it appears to be working so far.

According to Pitch f/x, Porcello hasn't thrown any sliders in 2013. This is how his slider performed in 2012:

2012	16.0%					Total
39.5% In Zone			60.5% Out Zone
33.1% Non-Swing	66.9% Swing		69.2% Non-Swing	30.8% Swing		45.0% Total Swing
	12.6% Non-Contact	87.4% Contact		45.2% Non-Contact	54.8% Contact	73.9% Total Contact

Hitters hit .394 against Porcello's slider last year, so there's a reason why he ditched it.
There isn't really any real conclusion from this due to the small sample size, but it looks like the sinker is the main problem and it shows as hitters are hitting .552 against it so far this year. A lot of that is probably due to his performance on Saturday, but that could be attributed to being unlucky.

One thing that is painfully obvious is that Porcello doesn't have an out pitch; something to where a batter will swing and miss at when he gets 2 strikes. It looks like his curveball won't be that pitch since literally every time they swing at it, they make contact. Like I mentioned earlier, Porcello has never been a strikeout pitcher and relies on contact, mainly ground balls, to get outs. When he has a performance like the one on Saturday, he can't buckle down and get a strikeout when he needs to.

I may revisit these numbers when we get a bigger sample later in the year.