Early Season Pitcher Workloads

by Mike Sonne

May 11, 2017

Traditional pitching metrics, such as innings pitched, and pitch counts, have often missed the mark when it comes to preventing pitcher injuries. As a result, I developed the Fatigue Units metric – which shows promise in illustrating how extreme workloads can influence pitchers in the subsequent seasons.

As a quick refresher – Fatigue Units are calculated by looking at an interaction between the number of pitches thrown, the velocity they are thrown at, the time taken between pitches, and the number of days between appearances. In the 2015 and 2016 season – these were your FU leaders.

2015 and 2016 Fatigue Units

Rank	Name	2015	2016	Total
1	Travis Wood	24.48	20.13	44.61
2	Dellin Betances	24.13	20.15	44.28
3	Chris Sale	21.92	21.51	43.43
4	Max Scherzer	20.38	20.16	40.54
5	Chris Archer	21.18	18.93	40.11
6	Johnny Cueto	21.85	17.92	39.77
7	Jeurys Familia	21.04	17.97	39.02
8	Yordano Ventura	19.49	19.24	38.73
9	Jake Arrieta	21.70	16.55	38.25
10	Randall Delgado	19.26	18.71	37.98
11	Roberto Osuna	18.00	19.82	37.82
12	Cole Hamels	19.93	17.57	37.50
13	Brad Brach	18.14	19.15	37.29
14	Zach Duke	17.12	19.84	36.97
15	Addison Reed	15.54	21.17	36.72
16	David Price	19.45	17.22	36.67
17	Erasmo Ramirez	17.74	18.83	36.57
18	Hector Santiago	19.95	16.60	36.55
19	Kyle Barraclough	15.99	20.50	36.48
20	Madison Bumgarner	18.35	18.03	36.38

Looking at the 2017 data for highest workloads, some pitchers have already starting racking up the fatigue units. Let’s dive in to see who has the highest workloads, and what teams appear to be mitigating those effects.

2017 Individual Fatigue Units and Workloads

Rank	Name	Fatigue Units	Days Between	Back to Backs	IP	Total Pitches	Game Apps	Pace (s)	Start IP	Relief IP
1	Felipe Rivero	6.20	2.00	8	19	297	19	21.6		19
2	Enny Romero	5.71	2.62	5	15.1	276	15	24.5		15.1
3	Brad Brach	5.57	2.06	7	18.2	297	18	23.8		18.2
4	Fernando Salas	5.31	2.06	7	15.1	287	18	25.9		15.1
5	Danny Farquhar	5.18	2.18	6	15	288	18	23.1		15
6	Bud Norris	5.06	2.25	5	18	306	17	27.6		18
7	Anthony Swarzak	4.96	2.09	5	14.2	195	12	25.3		14.2
8	Jhan Marinez	4.89	2.77	5	14	274	14	26.7		14
9	Joe Kelly	4.87	2.62	2	17	290	14	27.8		17
10	Yusmeiro Petit	4.82	2.91	3	19	296	12	24.5		19
11	Chris Sale	4.81	5.33	0	51.2	757	7	20.4	51.2
12	Tyler Clippard	4.78	2.27	6	14.1	227	16	27		14.1
13	Josh Smoker	4.71	2.29	2	16	311	15	22.4		16
14	Seung Hwan Oh	4.66	2.64	6	16.2	285	15	22.9		16.2
15	Brian Duensing	4.64	2.27	4	14	210	12	22.9		14
16	Miguel Diaz	4.61	2.57	3	15.1	260	15	24.8		15.1
17	Daniel Hudson	4.59	2.25	5	14.1	275	17	27.6		14.1
18	Joely Rodriguez	4.58	2.43	4	17.2	287	16	23.3		17.2
19	Chris Devenski	4.56	3.40	2	21	328	11	21.2		21
20	Hansel Robles	4.53	2.25	5	18.1	302	17	24.4		18.1

Felipe Rivero leads the MLB in workload so far, driven primarily by an astonishing 8 back to back appearances in 19 games. That is not a lot of time for recovery! He averages an outing once every 2 days – also the shortest in the MLB. It’s easy to see why though – he has an ERA under 1, on a team that has a historic number of blown leads so far. There’s a reason why certain pitchers can get to high workloads – they’re good.

Brad Brach is also sky rocketing up the workload charts with the injury to Zach Britton – and has appeared in 7 back to back games. These are very high workloads early in the season, but should tend to decrease as their respective teams either start winning games big, or losing games big.

2017 Team Fatigue Units and Workloads

Rank	Team	Fatigue Units	Days Between	Back to Backs	IP	Total Pitches	Game Apps	Pace (s)	Start IP	Relief IP
1	Mets	48.97	3.54	41	293.6	5052	159	22.93	173	119.9
2	Pirates	44.04	3.89	21	291.1	4776	124	23.20	182.2	108.9
3	Cubs	43.57	3.70	18	305.2	5268	147	22.52	176.4	128.8
4	Angels	43.36	3.93	18	310.1	5128	142	24.69	191.8	118.3
5	Padres	42.49	4.01	16	291.9	4788	134	22.56	184	106.5
6	Diamondbacks	42.40	3.66	19	296.5	5057	133	23.72	194.4	102.1
7	Marlins	41.73	3.79	21	284.2	4864	140	23.61	160.6	123.6
8	Rockies	41.53	3.79	14	304.2	4935	143	23.44	191.4	112.8
9	Cardinals	41.00	3.84	19	288.5	4798	137	22.96	188.5	100
10	Orioles	40.73	4.23	23	286.2	5027	129	24.13	173.7	112.5
11	Rays	40.23	3.90	23	309.7	5163	142	26.26	197.3	112.4
12	Blue Jays	40.18	3.85	17	296.4	4931	146	24.46	178.6	117.8
13	Brewers	39.98	3.84	26	279.7	4862	139	24.81	169.9	109.8
14	Dodgers	39.96	4.03	19	292.2	4755	138	25.92	183.5	108.7
15	Nationals	39.85	3.80	16	296	4985	132	24.09	201.1	94.9
16	Giants	39.78	3.84	18	297.6	4893	139	24.34	200.5	97.1
17	Mariners	39.76	3.74	15	291.2	4745	142	23.69	175.9	114.6
18	Athletics	39.16	4.20	15	287.7	4825	131	25.02	175.8	111.9
19	Reds	39.04	4.19	8	292.5	4906	131	21.89	162.4	130.1
20	Rangers	38.51	4.17	15	298.3	4972	132	24.49	198.9	99.4
21	Yankees	38.11	4.21	16	280.5	4525	123	23.54	183.6	96.9
22	Astros	37.98	4.06	14	297.6	4804	127	24.72	194.8	102.8
23	Indians	37.38	4.13	17	277.5	4610	121	23.27	186.7	90.8
24	Royals	37.20	4.05	16	286.5	4774	132	22.57	180	105.8
25	Red Sox	37.07	3.91	13	282.1	4787	128	25.30	186.4	95.7
26	Phillies	35.07	4.10	16	274.5	4591	127	23.74	169.6	104.9
27	Twins	34.92	4.15	14	263.5	4417	132	23.80	158.6	104.9
28	White Sox	34.78	4.03	15	268	4458	115	25.17	176.7	91.3
29	Tigers	33.70	3.66	15	269.7	4823	125	25.74	178.5	91.2
30	Braves	33.59	3.51	18	266.4	4293	127	22.78	169.8	96.6

When you look at the teams with the highest workloads, something very dramatic jumps out at you – the Mets already have 41 back to back appearances out of their bullpen. The next closest? The Brewers, with 26 back to back appearances. This is a landslide! Quite honestly, it brings to question the management of the bullpen – and as far as risk factors go, they have the second shortest time between pitching appearances – 3.54 days between appearance.

Of course – this is speculation when it comes to evaluating bullpens – particularly in the early going. Bad performances by the bullpen can really tax the pitchers who are performing in the early onset of the season – take for example, Felipe Rivero this year, and Roberto Osuna/ Joe Biagini last year. Skippers will turn to the guys who can get them the outs they require to finish off games. Over a long season – this tends to balance out. If not? Expect massive workloads on these high performing arms – but don’t be surprised if they end up on the DL in the coming seasons.

BAL	CHW	ATH
BOS	CLE	HOU
NYY	DET	LAA
TBR	KCR	SEA
TOR	MIN	TEX

ATL	CHC	ARI
MIA	CIN	COL
NYM	MIL	LAD
PHI	PIT	SDP
WSN	STL	SFG