Rick Porcello’s Improved Changeup

When Rick Porcello decided to ditch his slider this year, most people expected that it would be his curveball to show marked improvement since that was the pitch that he was substituting the slider for. Well so far, it's been the changeup that's shown much improvement.  

According to Pitch f/x pitch values/100, Porcello's changeup has a value of 3.63 so far this year. That's not only the best value pitch for Porcello this year, it's the best value pitch that he's ever had (0 is average, positive results are above average, negative results are below average).

Year	4-Seam FB	2-Seam FB	Cutter	Slider	Curveball	Changeup
2009	0.92	0.22	-1.38	-2.94	-1.49	-1.20
2010	0.45	0.09		-1.77	-3.81	0.44
2011	-0.13	-0.65		0.18	-0.84	-0.45
2012	-0.68	0.14		-3.84	0.65	0.07
2013	-2.10	-2.05		1.42	0.35	3.63

Of course, it's still May and so, "beware of small samples." Porcello has thrown a total of 543 pitches so far this year and only 98 of them have been changeups.  FanGraphs even tells us that these pitch values have little predictive values:

This statistic has limited predictive power. It can show you what pitches a pitcher has had success with in the past, but you should be careful in extrapolating those results and projecting the future. It’s a descriptive statistic, not a predictive one.

Looking deeper in Pitch f/x, we can see why his changeup has been so valuable.

Changeups	PA	HR	BB	K	AVG	OBP	SLG
2009	100	3	8	12	0.275	0.333	0.429
2010	80	0	1	13	0.253	0.263	0.304
2011	78	1	0	14	0.253	0.260	0.427
2012	103	3	7	14	0.240	0.291	0.406
2013	35	0	1	9	0.176	0.200	0.206

The one stat that jumps out at me the most is the strikeouts. Already Porcello has 9 strikeouts on the changeup in 35 PA, 5 less than his career high that took him 103 PA last year and 78 PA in 2011. Has Porcello finally gotten his strikeout pitch?

Here's how Porcello's changeup compares to his other pitches:

2013	PA	HR	BB	K	AVG	OBP	SLG
2-Seam FB	58	1	4	5	0.415	0.466	0.528
4-Seam FB	27	3	1	5	0.269	0.296	0.654
Curveball	17	1	1	2	0.125	0.176	0.375
Changeup	35	0	1	9	0.176	0.200	0.206

Again, the one stat that jumps out at me is the strikeouts. Historically, Porcello has gotten most of his strikeouts on his 2-Seamer (or sinker as he calls it). But this year it's come from the changeup. "Beware of the small samples" again; things could even out by the end of the year. However, I would like to see Porcello throw his changeup a little more often to see if there's something there. He already is throwing it more than he has in the past:

Year	Changeup %
2009	14.4%
2010	11.7%
2011	11.4%
2012	13.6%
2013	18.1%

Although, I'd like to see it be his 2^nd most frequent pitch, right after his 2-Seam FB (sinker):

Pitch Type	Percentage
4-Seam FB %	24.3%
2-Seam FB %	38.9%
Slider %	0.7%
Curveball %	18.1%
Changeup %	18.1%