Pitchers with Divergent Strikeout (& Walk) Rates (Part 2)
Last week, I examined pitchers whose strikeout per nine (K/9) increased while the strikeout per plate appearance (K%) dropped. This article focuses on the pitchers who saw their strikeout rates go in the opposite directions. Besides the strikeout divergers, I’m going to include the walk rate divergers since both player sets aren’t long.
These lists aren’t groundbreaking but I find them useful to point out and track pitchers who may be improving or getting worse their strikeout rate depending on which column is examined. For the pitchers examined below, they mainly saw their BABIP drop (from .327 to .251). With fewer guys on coming up each inning, the pitchers had few opportunities for strikeouts each inning.
Here are the pitchers with a minimum of 20 innings in 2016 and 2017 with divergent strikeout rates along with thoughts on some pitchers.
| 2016 | 2017 | 2016 | 2017 | 2016 | 2017 | 2016 | 2017 | 2016 | 2017 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Name | K% | K% | Diff | K/9 | K/9 | Diff | BABIP | BABIP | Diff | BB/9 | BB/9 | Diff | BB% | BB% | Diff |
| Gio Gonzalez | 22.4% | 22.7% | 0.4% | 8.7 | 8.4 | -0.3 | 0.316 | 0.258 | -0.058 | 3.0 | 3.5 | 0.5 | 7.7% | 9.6% | 1.8% |
| Mike Leake | 16.5% | 16.6% | 0.1% | 6.4 | 6.3 | -0.1 | 0.318 | 0.309 | -0.009 | 1.5 | 1.8 | 0.3 | 4.0% | 4.7% | 0.8% |
| Yovani Gallardo | 16.2% | 16.3% | 0.1% | 6.5 | 6.5 | 0.0 | 0.303 | 0.286 | -0.017 | 4.7 | 4.1 | -0.5 | 11.6% | 10.4% | -1.2% |
| Jose Urena | 15.6% | 15.6% | 0.1% | 6.2 | 6.0 | -0.2 | 0.297 | 0.249 | -0.049 | 3.1 | 3.4 | 0.3 | 7.8% | 8.8% | 1.1% |
| Felipe Rivero | 28.1% | 29.3% | 1.2% | 10.8 | 10.5 | -0.2 | 0.312 | 0.234 | -0.078 | 3.9 | 2.4 | -1.5 | 10.1% | 6.7% | -3.4% |
| Michael Blazek | 17.9% | 18.9% | 1.0% | 7.8 | 7.3 | -0.6 | 0.349 | 0.261 | -0.088 | 5.9 | 1.0 | -4.8 | 13.4% | 2.7% | -10.7% |
| Chris Hatcher | 23.8% | 24.5% | 0.8% | 9.5 | 9.5 | 0.0 | 0.296 | 0.294 | -0.002 | 4.6 | 3.2 | -1.5 | 11.6% | 8.2% | -3.4% |
| Luke Weaver | 27.0% | 28.6% | 1.6% | 11.1 | 10.7 | -0.4 | 0.386 | 0.335 | -0.051 | 3.0 | 2.5 | -0.4 | 7.2% | 6.8% | -0.4% |
| Josh Fields | 26.6% | 26.9% | 0.3% | 10.8 | 9.5 | -1.3 | 0.390 | 0.219 | -0.171 | 2.8 | 2.4 | -0.5 | 7.0% | 6.7% | -0.2% |
| Garrett Richards | 23.0% | 25.0% | 2.0% | 8.8 | 8.8 | 0.0 | 0.302 | 0.233 | -0.069 | 3.9 | 2.3 | -1.6 | 10.1% | 6.5% | -3.7% |
| Keone Kela | 30.0% | 33.8% | 3.8% | 11.9 | 11.9 | 0.0 | 0.304 | 0.179 | -0.124 | 4.5 | 4.0 | -0.5 | 11.3% | 11.3% | -0.1% |
| Chad Qualls | 14.5% | 15.3% | 0.8% | 6.1 | 5.9 | -0.1 | 0.328 | 0.264 | -0.063 | 2.5 | 2.7 | 0.2 | 5.9% | 6.9% | 1.0% |
| Zach Putnam | 26.3% | 32.1% | 5.8% | 9.9 | 9.3 | -0.5 | 0.324 | 0.111 | -0.213 | 3.6 | 1.0 | -2.6 | 9.7% | 3.6% | -6.1% |
| Alex Meyer | 24.8% | 25.7% | 0.9% | 10.3 | 10.0 | -0.3 | 0.324 | 0.255 | -0.069 | 6.0 | 5.6 | -0.4 | 14.5% | 14.4% | -0.2% |
| Alex Cobb | 15.4% | 17.3% | 1.9% | 6.5 | 6.4 | -0.1 | 0.355 | 0.282 | -0.073 | 2.9 | 2.2 | -0.7 | 6.7% | 5.9% | -0.8% |
Gio Gonzalez: The 32-year-old lefty collected 15 Wins with a nice sub-3.00 ERA. It was all BABIP (.258) driven. His strikeout rates diverged, walks were up (3.0 BB/9 to 3.5 BB/9), ERA estimators near 4.00 (career highs), and his fastball lost 1 mph for the second straight season. He’s going to end up on a ton of bust lists as he regresses. For 2017, evaluate correctly and buy in at a reasonable price, not his 2017 production.
Felipe Rivero: Every year I find the worst closer in the top flight to target (e.g. Giles last year) and for now it looks to be Rivero. While his BABIP dropped (.234) and should bounce back up, he had several other traits helping with his 2017 dominance (1.67 ERA). His fastball velocity jumped 3 mph bringing his K% near 30%. Additionally, his walk rate dropped back down (2.4 BB/9).
Luke Weaver: Weaver’s BABIP dropped from .386 to .335 but he has some traits which lead to high BABIPs. He effectively throws three pitchers, fastball, change, and a bad curve. The problem is that the fastball is the only one he can throw for strikes. If he is ahead in the count, he’s fine mixing his pitches and dominating hitters but if he falls behind, hitters can wait on fastballs in the zone. A good comp is Michael Pineda.
Alex Cobb: An improved BABIP helped keep his ERA reasonable. His 6.4 K/9 is almost not playable in most leagues. Among qualified starters, it was the 10th lowest value. Some relievers almost reached his 126 total strikeouts. I still see him as overrated.
Besides the strikeout divergers, here are all the walk rate divergers.
| 2016 | 2017 | 2016 | 2017 | 2016 | 2017 | 2016 | 2017 | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Name | BB% | BB% | Diff | BB/9 | BB/9 | Diff | BABIP | BABIP | Diff | K/9 | K/9 | Diff |
| Tanner Roark | 8.5% | 8.3% | -0.3% | 3.1 | 3.2 | 0.0 | 0.269 | 0.300 | 0.031 | 7.4 | 8.2 | 0.9 |
| Matt Moore | 8.6% | 8.5% | -0.1% | 3.3 | 3.5 | 0.2 | 0.285 | 0.320 | 0.034 | 8.1 | 7.6 | -0.4 |
| J.A. Happ | 7.5% | 7.4% | -0.2% | 2.8 | 2.8 | 0.1 | 0.268 | 0.302 | 0.034 | 7.5 | 8.8 | 1.3 |
| Hector Santiago | 10.1% | 10.0% | -0.1% | 3.9 | 4.0 | 0.1 | 0.260 | 0.263 | 0.004 | 7.1 | 6.5 | -0.6 |
| Tom Koehler | 10.7% | 10.5% | -0.2% | 4.2 | 4.3 | 0.1 | 0.298 | 0.313 | 0.015 | 7.5 | 7.7 | 0.2 |
| Marco Estrada | 9.0% | 8.8% | -0.2% | 3.3 | 3.4 | 0.1 | 0.234 | 0.295 | 0.061 | 8.4 | 8.5 | 0.1 |
| Clay Buchholz | 9.4% | 7.5% | -1.9% | 3.6 | 3.7 | 0.1 | 0.263 | 0.484 | 0.221 | 6.0 | 6.1 | 0.1 |
| Tyler Wilson | 5.8% | 5.7% | -0.1% | 2.3 | 2.3 | 0.0 | 0.301 | 0.358 | 0.058 | 5.3 | 5.3 | 0.0 |
| Vance Worley | 9.6% | 9.0% | -0.6% | 3.6 | 3.8 | 0.1 | 0.281 | 0.378 | 0.097 | 5.8 | 6.3 | 0.5 |
| Seung Hwan Oh | 5.8% | 5.7% | -0.1% | 2.0 | 2.3 | 0.2 | 0.270 | 0.319 | 0.048 | 11.6 | 8.2 | -3.4 |
| Tony Watson | 7.4% | 6.9% | -0.5% | 2.7 | 2.7 | 0.0 | 0.232 | 0.309 | 0.077 | 7.7 | 7.2 | -0.6 |
| Trevor Cahill | 12.3% | 11.8% | -0.5% | 4.8 | 4.8 | 0.0 | 0.246 | 0.326 | 0.080 | 9.0 | 9.3 | 0.3 |
| Luke Gregerson | 7.8% | 7.6% | -0.2% | 2.8 | 3.0 | 0.1 | 0.239 | 0.306 | 0.067 | 10.5 | 10.3 | -0.1 |
| Robert Gsellman | 8.1% | 7.7% | -0.5% | 3.0 | 3.2 | 0.1 | 0.325 | 0.303 | -0.023 | 8.5 | 6.2 | -2.3 |
| Carlos Carrasco | 5.7% | 5.8% | 0.1% | 2.1 | 2.1 | 0.0 | 0.289 | 0.307 | 0.018 | 9.2 | 10.2 | 0.9 |
| Sonny Gray | 8.1% | 8.4% | 0.3% | 3.2 | 3.2 | -0.1 | 0.319 | 0.269 | -0.050 | 7.2 | 8.5 | 1.3 |
| Jose Alvarez | 5.9% | 5.9% | 0.0% | 2.4 | 2.2 | -0.1 | 0.362 | 0.309 | -0.053 | 8.0 | 8.3 | 0.3 |
| Alex Claudio | 4.6% | 4.6% | 0.0% | 1.7 | 1.6 | -0.1 | 0.312 | 0.269 | -0.042 | 5.9 | 6.1 | 0.2 |
| Ryan Garton | 6.4% | 6.7% | 0.2% | 2.5 | 2.5 | -0.1 | 0.320 | 0.219 | -0.101 | 7.6 | 6.5 | -1.0 |
| Erik Goeddel | 8.9% | 9.0% | 0.1% | 3.5 | 3.4 | -0.1 | 0.277 | 0.286 | 0.008 | 9.1 | 10.2 | 1.2 |
| Darren O’Day | 9.9% | 10.0% | 0.1% | 3.8 | 3.6 | -0.2 | 0.260 | 0.256 | -0.004 | 11.0 | 11.3 | 0.3 |
| Chaz Roe | 11.3% | 11.4% | 0.1% | 4.2 | 4.2 | 0.0 | 0.286 | 0.250 | -0.036 | 11.2 | 11.0 | -0.3 |
Overall, the walk rate differences are barely noticeable and in each chase, they were BABIP drive. Again, higher BABIP drags out innings increase the walks per nine innings.
Robert Gsellman: Owners ha high hoped on Gsellman coming into the 2016 with his 94-mph fastball, 54% GB%, and 8.5 K/9. Nothing stuck. His strikeouts dropped to 6.2 K/9, fastball velocity dropped, ERA ballooned to over five and was a huge disappointment. A June hamstring injury slowed him some but he just wasn’t the same pitcher. While he did post a 3.50 ERA in the season’s second half, his ERA estimators were closer to five. Right now, there’s nothing to buy. He’s a NAPP, NAPP, NAPPA.
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.
Even though I had Luke Weaver this year, I have to admit I did not realize he had a 28.6% K rate (actually 29.6% as a starter). Among all starters who threw at least 40 IP as a starter, he was 8th out of 207 guys. He was sandwiched between Kershaw and Severino and ahead of Archer, Strasburg, deGrom, and so on.