Tom Koehler has the highest K/9 in a season, with 8.78 per nine innings in his rookie season in 2012.
| NAME | K/9 | SEASON | TM | G | W | L | W% | GS | ERA | SO | CG | SHO | SV | IP | H | ER | R | HR | BB | HBP | GF | IBB | TBF | WP | BB/9 | K/BB | HR/9 | K% | BB% | WHIP | BABIP | RA | ERA- | FIP | FIP- | H/9 | PRAA | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | T. Koehler | 8.78 | 2012 |  MIA | 8 | 0 | 1 | .000 | 1 | 5.40 | 13 | 0 | 0 | 0 | 13.1 | 15 | 8 | 8 | 4 | 2 | 0 | 0 | 1 | 56 | 0 | 1.35 | 6.50 | 2.70 | 23.2 | 3.6 | 1.27 | .297 | 5.40 | 140 | 5.49 | 145 | 10.13 | -2.6 |
| 2 | | T. Koehler | 7.68 | 2017 | TOT | 27 | 1 | 7 | .125 | 13 | 6.69 | 62 | 0 | 0 | 0 | 72.2 | 83 | 54 | 55 | 16 | 35 | 7 | 0 | 3 | 334 | 1 | 4.33 | 1.77 | 1.98 | 18.6 | 10.5 | 1.62 | .313 | 6.81 | 162 | 6.04 | 143 | 10.28 | -15.1 |
| 3 | | T. Koehler | 7.49 | 2016 | MIA | 33 | 9 | 13 | .409 | 33 | 4.33 | 147 | 0 | 0 | 0 | 176.2 | 176 | 85 | 93 | 22 | 83 | 5 | 0 | 7 | 774 | 9 | 4.23 | 1.77 | 1.12 | 19.0 | 10.7 | 1.47 | .298 | 4.74 | 109 | 4.59 | 115 | 8.97 | -12.1 |
| 4 | | T. Koehler | 7.20 | 2014 | MIA | 32 | 10 | 10 | .500 | 32 | 3.81 | 153 | 0 | 0 | 0 | 191.1 | 177 | 81 | 84 | 16 | 71 | 7 | 0 | 0 | 803 | 4 | 3.34 | 2.15 | 0.75 | 19.1 | 8.8 | 1.30 | .290 | 3.95 | 106 | 3.84 | 107 | 8.33 | -6 |
| 5 | | T. Koehler | 6.58 | 2015 | MIA | 32 | 11 | 14 | .440 | 31 | 4.08 | 137 | 0 | 0 | 0 | 187.1 | 180 | 85 | 96 | 22 | 77 | 6 | 0 | 3 | 800 | 2 | 3.70 | 1.78 | 1.06 | 17.1 | 9.6 | 1.37 | .283 | 4.61 | 108 | 4.52 | 120 | 8.65 | -16.5 |
| 6 | | T. Koehler | 5.79 | 2013 | MIA | 29 | 5 | 10 | .333 | 23 | 4.41 | 92 | 0 | 0 | 0 | 143.0 | 140 | 70 | 72 | 14 | 54 | 5 | 2 | 2 | 601 | 7 | 3.40 | 1.70 | 0.88 | 15.3 | 9.0 | 1.36 | .289 | 4.53 | 120 | 4.27 | 117 | 8.81 | -10.3 |
Phillies 
Mets 
Marlins 
Braves 
Nationals 
CLE 
BOS 
Brewers 
Cubs 
Dodgers 
Padres 
Blue Jays 
Tigers 
Astros 
Mariners 
NYY 
AZ 
PIT 
COL 
BAL 
TBR 
CIN 
MIN 
KCR 
CWS 
