Changing Fastballs

by
April 12, 2019

Most analysts listened when I made this pre-season request.

Almost too good. Every time I thought about writing about today’s topic, another writer stepped up. I’m done waiting and it is time to see which fastballs have changed, for the better or worse, since last year.

Instead of focusing just on velocity, I add in the fastball’s spin rate and the pitcher’s overall Zone%. With spin rate, I’ve seen pitchers try to keep up their velocity while dealing with an injury and the pitch’s spin changes. As for Zone%, if a pitcher is having issues finding the plate, they may have something mechanically wrong. By combining the three factors together, I’ve come up with an overall ‘Injury’ value where a -100 score means several negative forces are at work.

Besides just looking at the negatives, a pitcher can improve over time and these pitchers make ideal pickups. I’ll go over the pitchers who made the biggest gains and losses from 2018 to 2019. I’m going to stay away from weekly changes for now with the limited number of games, but all the numbers are available in this overall spreadsheet.

First, here are the pitchers who are headed down and a look at a few of them.

Degrading Pitchers
2018 2019 2018 to 2019
Name Pitch Velo Spin Count Zone% Velo Spin Count Zone% Injury
Chris Sale FF 95.2 2357 984 49% 91.1 2239 76 49% -107
Tim Hill SI 90.5 2092 342 55% 88.7 2042 20 34% -89
Jake Petricka FT 94.8 2104 520 43% 92.3 2060 13 32% -82
Tim Hill FF 91.5 2258 248 55% 90.0 2221 14 34% -80
Justin Anderson FF 97.3 2289 471 41% 94.4 2230 51 36% -80
Tony Sipp FF 91.8 2141 326 45% 89.1 2031 27 45% -74
Caleb Frare FF 93.8 2380 70 47% 92.2 2282 30 37% -72
Felix Pena FT 92.3 2206 707 49% 90.2 2122 49 42% -71
Matt Strahm FF 93.4 2399 579 54% 91.2 2303 69 52% -66
Jon Edwards FF 95.1 2479 80 51% 93.3 2468 36 38% -66
Kelvin Herrera FF 96.5 2215 308 48% 94.2 2160 27 45% -63
Jeanmar Gomez SI 91.6 2052 203 51% 90.7 1990 28 35% -63
Chris Archer FT 94.8 2214 250 47% 92.9 2131 31 45% -61
Hunter Wood FF 94.3 2470 367 46% 91.7 2402 31 49% -60
Tyler Kinley FF 96.7 2248 124 44% 94.7 2211 38 39% -59
Brad Hand FF 93.8 2476 354 51% 91.7 2387 44 51% -59
Carlos Rodon FF 92.9 2261 929 47% 91.5 2152 159 43% -58
Adam Cimber SI 86.1 2184 442 58% 84.7 2157 20 46% -57
Reynaldo Lopez FF 95.5 2102 1870 51% 93.3 2065 116 48% -57
Collin McHugh FF 92.1 2304 588 48% 89.8 2241 49 49% -57
Jared Hughes SI 91.6 1821 867 36% 90.5 1739 51 28% -55
Ivan Nova FF 93.1 2297 693 48% 91.4 2207 26 46% -55
Shane Greene FT 94.2 2218 497 52% 92.6 2182 40 44% -54
Mike Mayers FF 96.1 2351 548 48% 94.0 2325 55 46% -51
Brad Boxberger FF 91.3 2266 646 45% 89.7 2168 51 46% -50
Alex Claudio SI 86.0 1984 552 40% 83.9 1982 51 36% -49
Joe Musgrove FF 93.5 2349 522 54% 91.1 2464 38 42% -49
Chad Green FF 96.1 2444 1083 56% 94.8 2442 77 45% -49
Dakota Hudson SI 95.9 2191 251 49% 93.8 2203 97 44% -49
Stephen Strasburg FF 94.6 2122 980 48% 93.1 2084 91 42% -49

 

● Chris Sale: No surprise with him at the top. His velo drop has been well documented across the interwebs.

● Felix Pena: I was a small Pena fan coming into the season because of his above-average slider and change he threw last season. The breaking pitches are still productive, but his fastball velocity is down 3 mph. The drop started last season when he first moved to the rotation (93.5 mph), but it dropped to 92.0 mph by season’s end. Many pitchers experience this drop when moving from the bullpen to the rotation. His just took a while to stabilize.

Here is how his fastball has performed at different velocities.

Velo SwStr%
90 2.4%
91 2.3%
92 4.0%
93 4.3%
94 6.8%

It’d be nice to see it in the 92 mph range. One encouraging sign is that his velocity has trended up so far this season going from averaging 90.0 mph to 90.7 mph to 90.8 mph.

● Chris Archer: Archer rides a fine line to stay productive. He is a fastball/slider pitcher who relies on strikeouts to get by. Losing about 2 mph on his fastball could kill his fantasy value. The pitch has seen its swinging-strike rate drop from 6.5% to 5.1% and it’s Zone% from 52% to 46%. The results have been fine (2.45 ERA and 12.3 K/9) because his slider has a 35% SwStr%. Everything is all good but that could all end soon.

● Matt Strahm and Collin McHugh: Both are making the transition to the rotation and will see their velocity drop.

● Joe Musgrove: It’s tough to argue against someone with a 0.00 ERA. The results have been great but he’s done it with a fastball that has lost almost 2.5 mph. Additionally, the pitches in the strike zone are down 10% points. The slower fastball has not generated a single swinging strike.

But his non-fastballs have been great with his slider at a 40% SwStr%. He’s throwing the slider quite a bit more after dropping his cutter. A new pitch mix and a slower fastball mean a new talent level. It’s just tough to guess it properly three games into the season.

● Stephen Strasburg: A 1.5 mph drop and loss of strike-zone command are killing his value. The walks are up to a career high of 3.8 BB/9 and he’s getting hit around (1.1 HR/9, .311 BABIP) leading to 5.40 ERA. He needs to start pitching off his non-fastballs more but he’s gone the other direction. This season his fastball rate is up from 52% to 56%

That’s enough bad news. Now it’s time for some good news. Here are the pitchers heading in the right direction.

Improving Pitchers
2018 2019 2018 to 2019
Name Pitch Velo Spin Count Zone% Velo Spin Count Zone% Injury
Drew Pomeranz FT 88.4 2236 181 44% 91.5 2364 22 51% 101
Drew Pomeranz FF 89.5 2300 575 44% 92.0 2440 70 51% 93
Madison Bumgarner FT 90.8 2075 703 49% 90.8 2388 96 55% 74
Josh Hader FF 94.5 2041 1015 52% 95.6 2253 90 57% 73
Tyler Chatwood FT 92.6 2354 523 43% 94.7 2448 24 45% 65
David Hess FF 91.9 2171 1023 48% 93.7 2273 120 51% 64
Martin Perez FT 92.6 2012 710 45% 94.7 2078 49 51% 64
Thomas Pannone FF 88.0 2142 446 49% 90.4 2301 86 40% 61
Brock Stewart FT 91.0 2339 167 49% 92.7 2427 42 50% 55
Adrian Sampson SI 91.1 1983 195 49% 92.9 2071 78 49% 55
Corbin Burnes FF 95.3 2560 335 50% 94.6 2864 101 52% 52
Hector Velazquez FF 91.5 2095 323 48% 92.1 2207 31 57% 52
Sam Gaviglio SI 88.0 2040 1118 46% 89.5 2129 32 47% 49
Luke Jackson FF 94.3 2147 291 42% 95.4 2253 38 43% 47
Max Fried FF 93.1 2043 298 48% 94.4 2111 116 52% 47
Adam Conley FF 95.2 2261 440 46% 96.4 2361 52 47% 46
Hyun-Jin Ryu FF 90.3 2054 386 50% 90.7 2151 75 59% 45
Randy Rosario FF 93.5 1964 320 46% 94.1 2172 16 42% 44
Gerrit Cole FF 96.5 2379 1634 52% 96.9 2536 150 55% 44
Freddy Peralta FF 90.7 2389 1074 51% 92.2 2406 218 57% 44
Chase De Jong FF 89.2 2217 147 49% 91.1 2331 28 41% 44
Adam Ottavino FT 93.8 2287 529 49% 93.9 2433 38 55% 43
Joe Ross FF 93.2 2103 79 50% 94.3 2171 27 53% 42
John Gant FF 93.2 2442 290 49% 94.6 2526 16 47% 42
Chad Bettis FF 90.5 1879 797 47% 90.8 1979 45 55% 41
Tommy Kahnle FF 95.1 2223 264 46% 96.4 2297 41 46% 41
Robert Gsellman FT 94.0 2147 791 49% 95.1 2233 56 50% 40
Junior Guerra FF 93.1 2271 901 45% 94.2 2328 31 49% 40
Felix Hernandez SI 89.2 1997 830 44% 89.5 2061 44 55% 39
Miguel Castro SI 95.3 2261 859 48% 96.6 2364 84 45% 39

● Drew Pomeranz: He needs to be owned in all formats as he rebounds from last season’s bicep and neck issues. His fastball velocity is up at 92 mph. The last time his velocity was that high, he posted an 8.6 K/9 and 3.66 ERA in 2015. This year the strikeout rate is up to 11 K/9 with a 4.00 ERA this season.

● Madison Bumgarner: The once an elite pitcher may have put himself back on that mantle with an additional 300 RPMs of spin to each of his pitches.

Pitch: 2018 Spin, 2019 Spin
Cutter: 2130, 2430
Sinker: 2080, 2390
Curve: 2300, 2570

Someone has been talking to the Astros.

●Josh Hader: 94.5 mph to 95.6 mph. Good luck hitters.

● Corbin Burnes: He may have found the sticky stuff also. His fastball lost about half a tick, but its spin has gone from 2560 rpm to 2860 rpm. With the extra spin, the fastball has retained its swinging strike rate (10.5% to 10.9%) while losing velocity.





 

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 four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.

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crez33Member since 2018
6 years ago

I have a newbie question. What’s the difference between plate discipline and pitch info plate discipline? For example, on, say, Jeff Samard.’s page, his O-Swing% under the “Plate discipline” category is 22%, but his O-swing% under the “pitch info plate discipline” category is 22.2%.

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towerymt
6 years ago
Reply to  crez33

Short answer: different data sources. Now, some ramblings…

As for the reasons why they’re different…I’ve wondered myself. So I went searching and came up with this:

https://fantasy.fangraphs.com/which-source-for-pitching-metrics-is-best/

It looks like PITCHf/x is classifying strikes by location when there is no swing. The umpire’s call doesn’t seem to be a factor (my interpretation of the paragraph starting with “But, ah, yes, the complication:” in the article above). That makes sense. But does “Plate Discipline” do the same thing, just from a different data source (BIS)?

A borderline pitch that’s outside the zone according to PITCHf/x, but is called a strike by the ump, may not be counted the same by each system when calculating O-Swing. I don’t know what “Plate Discipline” (the BIS data source) is doing with pitches where there is no swing, but it’s either using the ump’s call to count it as a strike, or using it’s own definition of the strike zone to determine if it was in the zone or not. I would assume it would need a definition of the strike zone, else how could out-of-the-zone be determined when the batter swings?

I ran into difficultly last year when comparing the two data sources. I was trying to investigate Walker Buehler’s swinging strike rate (swstr%). His 2018 K rate was high (27.9%) for his 11.0 swstr%, so I went to Brooks Baseball to look at whiff percent on individual pitches. When I added up the total whiffs, divided by the total pitches, I got 12.5% whiff percentage from Brooks Baseball (PITCHf/x). I have no idea why Plate Discipline is only 11.0%…that’s a big difference.

3