Pitch Grades vs. Relative Pitch Grades

When deciding on the grade for a pitcher’s breaking pitch, a scout relies on the pitch’s velocity and movement (although command can be factored in as well).  These factors are combined into a single number on a scale from 20-80, with major league average as a 50 and a standard deviation recorded at 10.

Clayton Kershaw’s curveball has long been regarded as one of the best in the business, yet by my systematic calculation factoring in velocity, horizontal movement, and vertical movement, his curveball rated among the bottom third of curveballs.  Its below-average velocity and below-average horizontal movement held it back despite its above-average vertical movement.  While I was pondering this conundrum, I remembered another fact–Kershaw’s fastball happens to have a lot of rise.  What if movement was recorded by the difference between the pitcher’s fastball movement and the breaking ball movement instead of the breaking ball’s movement compared to an arbitrary point?  I was about to find out.

(This paragraph is solely methodology, so skip it if you wish.)  Using Baseball Prospectus’ excellent pitch f/x leaderboard, I selected all pitchers who threw at least 200 four-seam fastballs and at least 100 curveballs in 2014.  A breaking pitch’s horizontal and vertical movement was recorded as the difference between the pitch’s raw movement and the pitcher’s four-seam fastball’s movement.  I calculated the z-scores for the curveball’s velocity and the z score for the combination of the z scores of the curveball’s relative movements.  (I gave a 150% weight to vertical movement over horizontal movement).  Then, I combined the z scores of the velocity and combined relative movement to calculate a relative pitch score.  (I gave a 150% weight to combined relative movement over velocity).  Finally, I calculated a scouting grade on the 20-80 scale based off the relative pitch score.  Below is a table showing my results.

While I may not have solved the difference of evaluation among Kershaw’s curveball, the relative scouting grade at least opens discussion on how movement and velocity of pitches should be evaluated.  Is it better for a breaking pitch to be faster, or is it better to create a wider difference in velocity between the fastball and breaking ball?  Is it better for a pitcher’s breaking ball movement to be as different from the fastball as possible, or do some similarities create greater deception because a hitter can’t recognize the pitch earlier?

Player	CU Vel	CU H Mov	CU V Mov	Rel SG	Unadj SG
Garrett Richards	79.68	5.85	-12.33	76.26	71.63
Sonny Gray	82.45	9.21	-5.44	76.09	67.11
Justin Grimm	81.63	7.15	-6.92	72.63	64.67
Blaine Hardy	78.62	1.55	-9.74	71.28	53
Adam Wainwright	75.37	9.34	-9.23	69.59	60.71
John Axford	78.77	4.37	-9.81	69.07	59.61
Carlos Torres	79.9	6.43	-9.09	68.1	64.79
Robbie Erlin	74.28	0.81	-10.64	68.01	43.53
Felix Hernandez	80.97	7.25	-8.16	67.84	66.62
Yu Darvish	78.16	8.5	-7.46	67.83	60.8
Yordano Ventura	83.76	2.28	-5.63	65.12	55.81
Clay Buchholz	78.25	8.88	-7.36	64.52	61.56
Brandon Workman	77.09	4.68	-9.35	64.24	55.08
Tyler Skaggs	77.58	6.64	-8.92	63.97	59.31
Jake Arrieta	80.12	5.81	-9.46	63.55	64.97
Juan Gutierrez	81.1	6.16	-6.77	62.94	60.89
Kevin Jepsen	84.52	3.9	-6.89	62.68	64.44
James Paxton	82.54	0.39	-2.69	62.49	41.05
Chris Tillman	76.22	3.31	-10.43	62.3	52.94
Craig Kimbrel	86.3	4.84	-5.95	62.14	68.18
Adam Warren	81.94	4.9	-6.62	61.45	59.77
Dellin Betances	83.85	7.04	-3.79	61.29	61.37
Edinson Volquez	80.67	5.95	-7.3	60.89	60.83
Wade Davis	85.56	3.29	-4.69	60.28	59.75
Tom Wilhelmsen	78.85	6.01	-7.58	60.26	57.4
Trevor May	77.76	7.56	-6.23	59.46	54.56
Cody Allen	86.88	5.09	-3.71	59.12	64.13
Tyler Thornburg	78.45	2.83	-7.21	59.01	48.63
Casey Janssen	74.81	9.84	-5.38	58.98	50.23
Trevor Bauer	79.18	5.17	-8.33	58.51	58.36
Brad Peacock	77.37	5.91	-7.39	57.85	53.18
Brett Oberholtzer	79.73	1.73	-3.22	57.83	38.69
Cole Hamels	79.01	3.23	-6.2	57.81	48.13
Josh Tomlin	76.76	4.39	-7.46	56.34	48.65
Drew Pomeranz	81.77	4.9	-7.41	56.24	61.47
Gio Gonzalez	78.4	5.35	-8.64	56.18	57.73
Andre Rienzo	79.26	6.3	-6.52	55.97	56.17
Scott Atchison	80.83	4.81	-8.52	55.78	62
Scott Kazmir	77.03	0.12	-3.35	55.77	29.19
Ian Kennedy	78.23	6.26	-9.1	55.71	60.51
Nick Tepesch	78.82	5.36	-8	55.71	57.04
Cory Rasmus	76.65	5.44	-7.84	55.67	51.66
Tom Koehler	79.92	5.1	-8.64	55.42	60.79
Marco Estrada	77.92	4.66	-6.27	55.31	48.81
Mike Fiers	72.93	3.7	-11.31	55.29	48.33
Odrisamer Despaigne	76.43	8.24	-7.25	55.08	55.59
Francisco Rodriguez	76.96	7.14	-6.73	54.97	53.1
Anthony Ranaudo	78.16	4.35	-7.93	54.82	53.13
Stephen Strasburg	80.69	7.59	-7.28	54.74	64.35
Mike Minor	81.66	0.98	-3.82	54.69	43.24
Yovani Gallardo	79.95	4.01	-6.75	54.68	53.49
Jeremy Hellickson	76.7	7.51	-9.53	54.53	60.71
Justin Verlander	79.98	4.97	-6.45	54.29	54.83
Dillon Gee	74.91	8.15	-7.75	54.19	53.13
J.A. Happ	78.27	2.13	-4.71	53.89	40.06
Kevin Quackenbush	77.17	5.05	-7.88	53.7	52.15
Roenis Elias	79.81	7.16	-6.09	53.3	58.18
Marcus Stroman	83.34	8.96	-2.3	53.27	60.33
Jason Vargas	75.68	1.63	-5.08	53.05	33.84
Clayton Kershaw	74.61	2.35	-8.93	52.85	43.08
Collin McHugh	73.68	8.26	-9	52.55	53.77
David Phelps	80.72	2.7	-5.06	52.51	48.01
Tommy Hunter	83.55	6.01	-3.14	52.48	56.72
Wesley Wright	79.8	3.86	-4.65	52.48	47.24
Miles Mikolas	75.4	6.22	-9.7	52.36	55.32
Javy Guerra	77.99	3.47	-7.42	52.2	49.48
Jason Hammel	77.19	6.3	-7.76	52.1	54.57
Vic Black	82.68	3.57	-3.91	51.95	51.46
Phil Coke	80.48	0.98	-3.37	51.9	39.25
Nick Martinez	76.92	3.84	-8.05	51.86	49.41
Jordan Zimmermann	79.71	5.65	-6.73	51.77	56.4
Phil Hughes	77.22	6.62	-7.84	51.53	55.54
Zack Greinke	72.88	6.58	-7.08	51.41	43.17
Colby Lewis	77.7	6.12	-5.81	50.97	50.21
Joe Kelly	79.88	6.94	-8.44	50.7	64.12
David Price	80.37	2.84	-1.58	50.68	38.24
Tim Lincecum	75.63	3.81	-8.37	50.62	47.15
Junichi Tazawa	76.12	6.87	-8.14	50.61	54.27
Matt Garza	75.25	4.66	-8.62	50.4	48.74
Jake Peavy	80.56	2.49	-1.91	50.39	38.81
Joba Chamberlain	79.74	5.1	-6.03	50.25	53.43
John Lackey	79.16	5.54	-5.39	50.13	51.3
Grant Balfour	82.74	2.44	-1.31	50.07	42.27
Wei-Yin Chen	74.9	3.11	-6	50	37.62
Danny Duffy	78.22	3.8	-6.76	49.95	48.98
Michael Wacha	75.4	4.99	-6.15	49.88	43.24
Zack Wheeler	79.61	6.2	-8.2	49.75	61.25
Anthony Varvaro	80.73	4.14	-5.43	49.68	52.11
Shelby Miller	77.76	7.65	-5.21	49.51	52.05
Edwin Jackson	79.94	1.31	-3.97	49.41	40.28
Miguel Gonzalez	77.47	5.77	-6.3	49.39	50.22
Anibal Sanchez	79.85	3.27	-3.53	49.35	43.11
Jesse Hahn	74.64	8.63	-8.05	49.33	54.32
Brandon McCarthy	82.24	5.96	-4.24	49	56.44
Mat Latos	76.95	3.64	-4.84	48.99	40.53
Tanner Roark	74.25	6.13	-9.04	48.69	50.65
Vance Worley	77.87	6.06	-5.44	48.53	49.5
J.J. Hoover	75.78	6.82	-6.21	48.49	48.24
Jose Fernandez	83.56	8.96	-1.82	48.41	59.58
Felix Doubront	75.43	2.87	-8.77	48.33	45.72
Jordan Lyles	81.77	2.16	-3.92	48.31	46.3
Santiago Casilla	82.01	4.48	-5.46	48.18	55.95
Kevin Correia	79.47	6.02	-3.46	48.15	47.94
Erik Bedard	74.86	4.96	-6.51	48.07	42.86
James Shields	80.39	3.11	-4.08	47.79	45.51
Gerrit Cole	84.65	6.34	-3.47	47.79	60.91
Chase Anderson	77.79	4.59	-7.32	47.24	51.15
Rick Porcello	78.15	7.45	-5.93	46.98	54.45
Travis Wood	72.92	1.78	-6.47	46.64	31.32
Samuel Deduno	81.59	6	-5.39	46.63	58.04
Johnny Cueto	81.53	2.02	-1.73	45.52	39.62
David Buchanan	77.95	4.31	-8.22	45.48	53.31
Ian Krol	79.05	5.17	-4.38	45.11	47.56
Erasmo Ramirez	80.4	3.22	-1.79	45.05	39.68
Charlie Morton	78.99	9.72	-7.1	45.02	64.43
Matt Cain	78.2	7.49	-5.26	44.99	52.88
Jose Quintana	80.94	2.22	-2.39	44.96	40.41
A.J. Burnett	82.4	4.23	-5.31	44.89	55.94
Vidal Nuno	77.29	4.84	-5.16	44.68	44.76
Daisuke Matsuzaka	75.37	8.38	-6.13	44.63	50.41
Hector Noesi	81.07	5.54	-4.12	44.59	52.45
Jake Odorizzi	70.24	4.97	-8.77	44.52	37.95
Joel Peralta	78.14	5.41	-3.91	44.15	44.68
Joe Nathan	82.63	2.69	-1.83	43.9	43.93
Carlos Carrasco	81.71	6.55	-5.33	43.55	59.35
Josh Beckett	73.88	7.73	-7.83	43.33	50
Fernando Salas	83.76	1.47	1.74	43.17	34.49
Lance Lynn	80.15	4.98	-5.79	43.07	53.5
Jered Weaver	69.96	6.47	-3.84	42.49	27.42
Will Smith	79.06	4.48	-4.32	41.86	45.94
Hector Santiago	77.64	3.59	-0.53	41.31	30.6
Jorge De La Rosa	74.81	4.56	-6.26	41.19	41.21
Hyun-jin Ryu	73.1	5.04	-7.88	41.17	42.5
Matt Shoemaker	76.24	6.77	-1.78	41.06	37.45
Fernando Abad	78.63	4.08	-4.74	40.75	45.18
Ryan Vogelsong	77.55	2.32	-4.13	40.71	37.22
Nathan Eovaldi	76.8	7.12	-7.37	40.45	54.37
Jon Niese	74.5	2.71	-5.81	39.94	35.31
Dan Haren	77.88	3.67	-3.65	39.66	39.63
Brad Hand	80.04	5.66	-2.5	39.15	45.96
Franklin Morales	74.71	5.81	-5.22	38.68	40.9
Alfredo Simon	78.2	5.32	-4.82	38.35	47.04
Eric Stults	68.63	1.8	-5.12	37.89	17.63
Madison Bumgarner	77.56	5.55	-4.39	37.85	44.88
Yusmeiro Petit	77.55	7.25	1.56	37.82	32.71
Jeremy Guthrie	76.14	4.86	-3.22	37.74	36.93
Masahiro Tanaka	74.41	5.28	-6.35	37.48	42.06
Gavin Floyd	81.7	5.13	-3.23	37.24	50.69
Aaron Harang	74.67	2.85	-4.36	36.79	32.16
Jacob deGrom	80.26	4.49	-1.82	36.32	42.16
Jon Lester	75.95	4.82	-4.15	36.25	38.87
Homer Bailey	80.44	5.72	-2.91	36.13	48.13
Jose Veras	76.8	10.11	-5.62	35.11	56.15
Jerry Blevins	74.84	6.77	-4.32	35.1	40.88
Drew Smyly	78.4	3.38	-0.21	34.68	31.1
C.J. Wilson	77.18	5.52	-4.61	34.67	44.5
John Danks	74.15	2.51	-1.84	34.63	23.5
Julio Teheran	74.02	6.32	-4.89	34.54	39.49
Jacob Turner	79.14	3.29	-2.46	34.4	38.63
Tommy Milone	75.46	4.13	-2.38	34.24	31.52
Tim Hudson	76.14	8.32	-4.29	33.02	47.21
Max Scherzer	78.2	5.92	-2.31	32.64	41.66
Hiroki Kuroda	77.15	4.58	-2.65	31.98	37.2
Paul Maholm	72.76	5.41	-5.55	29.91	36.31
Carlos Villanueva	76.58	4.05	-1.53	29.9	31.74
Scott Carroll	77.43	7.38	-2.75	25.13	44.15
Mark Buehrle	72.16	3.91	-3.74	23.02	26.85