Stealing First

Looking at Pitches on the Edges

Posted by Dan Turkenkopf - 12/05/08 at 09:05:06 am

My latest post is up at Beyond the Box Score – looking at how umpires “mistakes” are affected by various splits on pitches near the edge of the strike zone.

Revisiting the Run Value of Switching a Ball to a Strike

Posted by Dan Turkenkopf - 01/05/08 at 08:05:18 am

Over at Beyond the Box Score, a commenter named Iblemetrician suggested that I reconsider how I calculated the value of switching a ball to a strike.

When I originally calculated the run value of a ball to a strike, I looked at all plate appearances for a given count. That came out to a run value of .161 runs Iblemetrician pointed out that certain counts will have more pitches taken – and even potentially have more pitches on the edge, which might be more likely to be miscalled.

With those suggestions (and after a little bit of programming), I went back and calculated a run value weighting by both called pitches and called pitches on the edges of the strike zone.

Let’s look at the same sort of table as in the first post – this time weighted by called pitches.

B	S	WOBA	LW	RV Ball	RV Strike	RV B->S	Called Pitches	Weighted RV
0	0	0.332	0	-0.0339	0.0426	0.0765	125879	0.0275
0	1	0.283	-0.0426	-0.0269	0.0617	0.0886	43120	0.0109
0	2	0.212	-0.1043	-0.02174	0.2007	0.2224	18148	0.0115
1	0	0.371	0.0339	-0.0626	0.0496	0.1122	41330	0.0132
1	1	0.314	-0.0157	-0.0504	0.0670	0.1174	31151	0.0104
1	2	0.237	-0.0826	-0.0461	0.2224	0.2685	22982	0.0176
2	0	0.443	0.0965	-0.1104	0.0617	0.1722	14736	0.0072
2	1	0.372	0.03478	-0.1026	0.0713	0.1739	14442	0.0072
2	2	0.29	-0.0365	-0.0983	0.2685	0.3667	16318	0.0171
3	0	0.57	0.2070	-0.1170	0.0696	0.1866	7308	0.0039
3	1	0.49	0.1374	-0.1866	0.0757	0.2623	6898	0.0052
3	2	0.403	0.0617	-0.2623	0.3667	0.629	7686	0.0138

Run Value of Switching a Ball to a Strike – Weighted by Called Pitches

Now let’s look at the same breakdown, but considering called pitches on the edge. These are pitches within 2 ball radii of any side of the strike zone (and within the strike zone on the other dimension). That means we’ll count the pitch if it’s one ball width outside the strike zone on the left and middle of the strike zone in height, but we won’t count it if it’s one ball width outside the strike zone on the left and three balls widths outside the zone high.

B	S	WOBA	LW	RV Ball	RV Strike	RV B->S	Called Pitches on the Edges	Weighted RV
0	0	0.332	0	-0.0339	0.0426	0.0765	25248	0.0292
0	1	0.283	-0.0426	-0.0269	0.0617	0.0886	7857	0.0105
0	2	0.212	-0.1043	-0.02174	0.2007	0.2224	2581	0.0087
1	0	0.371	0.0339	-0.0626	0.0496	0.1122	8383	0.0142
1	1	0.314	-0.0157	-0.0504	0.0670	0.1174	5895	0.0105
1	2	0.237	-0.0826	-0.0461	0.2224	0.2685	3533	0.0143
2	0	0.443	0.0965	-0.1104	0.0617	0.1722	2961	0.0077
2	1	0.372	0.03478	-0.1026	0.0713	0.1739	2817	0.0074
2	2	0.29	-0.0365	-0.0983	0.2685	0.3667	2687	0.0149
3	0	0.57	0.2070	-0.1170	0.0696	0.1866	1499	0.0042
3	1	0.49	0.1374	-0.1866	0.0757	0.2623	1376	0.0055
3	2	0.403	0.0617	-0.2623	0.3667	0.629	1318	0.0125

Run Value of Switching a Ball to a Strike – Weighted by Called Pitches on the Edges

I’m a little worried about sample size here – at least comparatively. The results back up the expected behavior though. Players are less likely to take a close pitch with two strikes than otherwise – which lowers the relative run value of those events and therefore the overall run value of “mistakes”.

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