# Pitcher Injury Finder & Fastball Grades

Fastball velocity changes may be getting beat to death but they are one of the few stats in which stabilize early in the offseason. I’ve created a couple tools which I use during the season to help find which pitchers to evaluate further using velocity. I have one which grades fastballs and a new pitcher injury finder.

This tool simply gives an ERA and 20-80 grade to a fastball based on its projected results from its velocity and spin. The velocity component is simple to understand. It’s hard to hit fast flying small objects. It’s even harder to hit faster flying small objects. Understanding the spin component is a little tougher.

The spin dictates how much a pitch will drop or rise. Hitters are used to a certain speed fastball having a set flight path to the plate. If the spin is more or less than normal, the ball will drop more or less and the hitter will make contact under or over their desired contact point. Too high on the ball means a ground ball. Too low, a popup.

It is ideal for a pitcher to have his fastball spin rate as far as possible from the norm. For a reference, here are the average fastball spin values for various pitch velocities

Average Fastball Spin at Different Velocities
Velocity Spin
86 2093
87 2112
88 2142
89 2158
90 2172
91 2180
92 2202
93 2228
94 2249
95 2269
96 2283
97 2294
98 2327
99 2373
100 2407

As it can be seen, the harder a pitcher throws, normally the ball spins more.

So using velocity and spin, I can estimate the pitch’s swinging strike rate and groundball rate from past results. Then, I inputted the values into my pERA equation and came up with an ERA for just that pitch. Finally, I took the pERA values, found the average value and gave it a grade of 50 (average major league fastball). For each standard deviation above average, the grade goes up by 10 with 80 being the best and 20 the worst.

With the explanation out of the way, here are the top and bottom ten fastballs in the league so far (full list).

Best and Worst Fastballs
NAME Pitch Count Velo Spin pERA Grade
Jordan Hicks SI 38 98.7 2129.4 3.99 75
Tayron Guerrero FF 79 97.7 2092.5 4.08 72
Jose Alvarado FT 32 98.0 2167.3 4.09 71
Noah Syndergaard FF 27 97.5 2147.8 4.13 70
Aroldis Chapman FF 61 98.6 2509.0 4.13 70
Joe Kelly FT 52 97.2 2098.6 4.14 69
Noah Syndergaard SI 64 97.2 2137.6 4.16 69
Arodys Vizcaino FT 44 98.0 2406.5 4.17 68
Luis Severino FF 90 97.6 2337.1 4.20 68
Shohei Ohtani FF 81 97.1 2199.7 4.20 67
Kyle Hendricks FF 30 87.3 2093.6 5.22 30
Brian Johnson FF 59 87.7 2163.1 5.22 30
Nestor Cortes FF 54 87.9 2210.4 5.23 30
Bartolo Colon FT 84 87.1 2140.8 5.27 28
Mike Fiers FF 41 87.3 2271.2 5.32 26
Brent Suter FF 101 86.3 2116.1 5.34 26
Alex Claudio SI 33 84.2 1899.1 5.38 25
Darren O’Day FF 29 86.8 2354.9 5.41 23
Adam Cimber SI 32 86.0 2166.6 5.42 23
Brad Ziegler SI 39 82.6 1836.0 5.47 21

Now, other fastball factors can be in-play besides velocity and spin like deception, control, command, and sequencing. It’s a quick-and-dirty test for a snapshot to help find pitchers to investigate further.

At some point in the future, I’d love to be able to run this process with any pitch but for now, it’s just fastballs.

Pitcher Injury Finder

I created a pitcher injury finder a while back but my computer died during a backup this past fall and I lost a ton of my programs. So, I recreated a basic program from what I remember of the previous inputs. I haven’t had a chance to run every test, so it’s a crude version but it’s at least up and running.

Its inputs, for now, are just fastball velocity, fastball spin rate, and Zone% with consistent release point to be added soon. I’d rather be a little off right now and keep adjusting the inputs than have nothing.

For the overall metric, a value of -100 means the pitcher’s traits point to worsening of his stats (e.g. velocity drop). A positive value means his traits are getting better (healthier).

With the season just getting underway, I’ll provide just information on the full 2017 and 2018 seasons. Later, I’ll look at just the past few days. Here is a list of the 20 pitchers who are most likely to be pitching injured and the 10 who show signs of being healthy (full list).

Hurt & Healthy Pitchers (4/10/18)
2017 2018
Name Pitch Velo Spin Zone% Count Velo Spin Zone% Count Injury Factor
Matt Boyd FT 91.0 2305 51% 249 87.1 2212 47% 12 -105
Jared Hughes FT 93.1 2071 37% 58 91.5 1769 32% 28 -103
Sam Tuivailala FF 95.6 2286 53% 361 92.0 2194 52% 23 -94
Daniel Stumpf FF 93.7 2441 53% 370 91.6 2255 49% 33 -88
Jared Hughes SI 93.6 2084 37% 413 91.8 1875 32% 13 -88
Matt Boyd FF 92.3 2248 51% 901 88.4 2246 47% 31 -87
Craig Kimbrel FF 98.3 2425 51% 786 96.0 2370 37% 60 -85
Blaine Boyer FT 93.9 2341 52% 99 91.3 2227 47% 12 -84
Michael Wacha FF 94.9 2155 50% 1238 92.8 2058 40% 75 -81
Brandon Maurer FF 96.5 2368 54% 552 94.7 2282 40% 36 -80
Jordan Zimmermann FT 92.2 2258 52% 179 90.4 2084 48% 17 -79
Jack Flaherty FT 92.5 2123 50% 92 90.2 2081 37% 18 -78
Dan Jennings FT 91.8 2276 49% 140 89.7 2230 37% 26 -77
Tommy Kahnle FF 97.8 2280 51% 599 95.3 2270 39% 42 -76
Yovani Gallardo FF 92.3 2144 46% 502 90.5 2066 34% 11 -76
Trevor Williams SI 90.4 1862 45% 379 88.6 1736 38% 27 -75
AJ Ramos FT 92.2 2201 44% 118 90.0 2155 33% 12 -75
Shane Greene FT 95.0 2299 54% 569 94.0 2127 44% 27 -74
JC Ramirez FF 95.6 2059 52% 137 92.5 1982 54% 50 -74
Brad Brach FF 95.0 2350 49% 698 93.1 2313 34% 57 -74
Hector Velazquez SI 88.9 2002 51% 118 90.7 2052 49% 20 42
Taijuan Walker FF 93.7 2104 47% 1386 94.0 2200 55% 126 42
Trevor Gott FF 93.1 2004 42% 79 94.8 2076 39% 25 43
Roberto Osuna FF 94.8 2424 44% 256 94.9 2399 67% 36 43
Mike Mayers FF 93.4 2227 52% 57 95.1 2306 53% 24 51
Adam Ottavino FT 94.2 2155 47% 209 94.3 2352 53% 28 53
Kendall Graveman FT 92.4 2302 41% 131 94.1 2376 49% 93 68
Yacksel Rios FT 93.2 1984 48% 69 94.7 2176 54% 14 80
Tyler Glasnow FF 94.4 2214 46% 612 95.7 2483 50% 52 89
Tyler Glasnow FT 94.0 2133 46% 189 95.6 2442 50% 30 102

JC Ramirez is already done for the season after needing Tommy John surgery, but probably the biggest name on the injured list is Craig Kimbrel with a huge velocity drop.

While he still hasn’t allowed a run to score, his strikeouts are down and walks up in the small sample.

Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

Member
jjeziora

Hey Jeff, how far off is Marcus Stroman from the injury risk leaderboard? He is showing nearly -2 mph velocity, as well as almost 10% loss in Zone% so far from 2017-2018.

Member
CJ03

if you click on the Full List, Stroman is a -37 injury Factor.

Another pitcher I’m worried about is Luis Castillo, who has also lost 2-3mph. His injury factor is -40

Member
Member
omar207

Thanks a lot Jeff, but GO BRUINS!