Buck O'Brien has pitched the most innings with an ERA better than 0.38 in a season, with 47.2 innings in his rookie season in 1911.
| NAME | IP | ERA | SEASON | TM | G | W | L | W% | GS | SO | CG | SHO | SV | H | ER | R | HR | BB | HBP | GF | IBB | TBF | WP | K/9 | BB/9 | K/BB | HR/9 | K% | BB% | WHIP | BABIP | RA | ERA- | FIP | FIP- | H/9 | PRAA | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | B. O'Brien | 47.2 | 0.38 | 1911 |  BSA | 6 | 5 | 1 | .833 | 5 | 31 | 5 | 2 | 0 | 30 | 2 | 9 | 0 | 21 | 1 | 1 | 189 | 0 | 5.85 | 3.97 | 1.48 | 0.00 | 16.4 | 11.1 | 1.07 | .221 | 1.70 | 11 | 2.85 | 88 | 5.66 | 2 | |
| 2 |  | D. Williams | 27.0 | 0.33 | 2020 |  MIL | 22 | 4 | 1 | .800 | 0 | 53 | 0 | 0 | 0 | 8 | 1 | 4 | 1 | 9 | 1 | 1 | 0 | 100 | 3 | 17.67 | 3.00 | 5.89 | 0.33 | 53.0 | 9.0 | 0.63 | .194 | 1.33 | 7 | 0.85 | 19 | 2.67 | 10.8 |
| 3 |  | E. Moore | 26.0 | 0.00 | 1908 |  PHN | 3 | 2 | 1 | .667 | 3 | 16 | 3 | 1 | 0 | 20 | 0 | 4 | 0 | 8 | 2 | 0 | 102 | 1 | 5.54 | 2.77 | 2.00 | 0.00 | 15.7 | 7.8 | 1.08 | .263 | 1.38 | 0 | 2.02 | 83 | 6.92 | 1.2 | |
| 4 |  | J.P. Feyereisen | 24.1 | 0.00 | 2022 |  TBR | 22 | 4 | 0 | 1.000 | 2 | 25 | 0 | 0 | 1 | 7 | 0 | 1 | 0 | 5 | 0 | 3 | 0 | 86 | 0 | 9.25 | 1.85 | 5.00 | 0.00 | 29.1 | 5.8 | 0.49 | .125 | 0.37 | 0 | 1.67 | 44 | 2.59 | 5.9 |
| 5 |  | J. Chamberlain | 24.0 | 0.38 | 2007 |  NYY | 19 | 2 | 0 | 1.000 | 0 | 34 | 0 | 0 | 1 | 12 | 1 | 2 | 1 | 6 | 1 | 3 | 0 | 91 | 1 | 12.75 | 2.25 | 5.67 | 0.38 | 37.4 | 6.6 | 0.75 | .224 | 0.75 | 8 | 1.81 | 41 | 4.50 | 7 |
| 6 |  | T. Olson | 20.0 | 0.00 | 2017 |  CLE | 30 | 1 | 0 | 1.000 | 0 | 18 | 0 | 0 | 1 | 13 | 0 | 0 | 0 | 6 | 1 | 4 | 0 | 77 | 0 | 8.10 | 2.70 | 3.00 | 0.00 | 23.4 | 7.8 | 0.95 | .250 | 0.00 | 0 | 2.40 | 55 | 5.85 | 4.4 |
| 7 | | H. Coveleski | 20.0 | 0.00 | 1907 | PHN | 4 | 1 | 0 | 1.000 | 0 | 6 | 0 | 0 | 0 | 10 | 0 | 2 | 0 | 3 | 1 | 4 | 72 | 0 | 2.70 | 1.35 | 2.00 | 0.00 | 8.3 | 4.2 | 0.65 | .161 | 0.90 | 0 | 2.18 | 83 | 4.50 | 1 | |
| 8 |  | C. Flexen | 18.1 | 0.00 | 2025 |  CHC | 11 | 4 | 0 | 1.000 | 0 | 10 | 0 | 0 | 1 | 10 | 0 | 1 | 0 | 5 | 0 | 9 | 0 | 67 | 1 | 4.91 | 2.45 | 2.00 | 0.00 | 14.9 | 7.5 | 0.82 | .192 | 0.49 | 0 | 2.79 | 72 | 4.91 | 2.3 |
| 9 | | D. Pomeranz | 18.1 | 0.00 | 2025 | CHC | 20 | 2 | 1 | .667 | 2 | 16 | 0 | 0 | 1 | 7 | 0 | 1 | 0 | 5 | 3 | 5 | 0 | 66 | 0 | 7.85 | 2.45 | 3.20 | 0.00 | 24.2 | 7.6 | 0.65 | .167 | 0.49 | 0 | 2.63 | 68 | 3.44 | 2.6 |
| 10 |  | K. Spooner | 18.0 | 0.00 | 1954 |  BKN | 2 | 2 | 0 | 1.000 | 2 | 27 | 2 | 2 | 0 | 7 | 0 | 0 | 0 | 6 | 0 | 0 | 68 | 0 | 13.50 | 3.00 | 4.50 | 0.00 | 39.7 | 8.8 | 0.72 | .200 | 0.00 | 0 | 0.40 | 10 | 3.50 | 7.3 | |
| 11 |  | F. Valenzuela | 17.2 | 0.00 | 1980 |  LAD | 10 | 2 | 0 | 1.000 | 0 | 16 | 0 | 0 | 1 | 8 | 0 | 2 | 0 | 5 | 0 | 4 | 0 | 66 | 0 | 8.15 | 2.55 | 3.20 | 0.00 | 24.2 | 7.6 | 0.74 | .178 | 1.02 | 0 | 1.78 | 49 | 4.08 | 3.6 |
| 12 | | B. Wieck | 17.0 | 0.00 | 2021 | CHC | 15 | 0 | 0 | 0 | 28 | 0 | 0 | 0 | 10 | 0 | 0 | 0 | 10 | 0 | 5 | 0 | 71 | 0 | 14.82 | 5.29 | 2.80 | 0.00 | 39.4 | 14.1 | 1.18 | .303 | 0.00 | 0 | 1.63 | 39 | 5.29 | 4.9 | |
| 13 |  | M. Norris | 16.2 | 0.00 | 1975 |  OAK | 4 | 1 | 0 | 1.000 | 3 | 5 | 1 | 1 | 0 | 6 | 0 | 2 | 0 | 8 | 0 | 0 | 0 | 65 | 0 | 2.70 | 4.32 | 0.63 | 0.00 | 7.7 | 12.3 | 0.84 | .115 | 1.08 | 0 | 3.42 | 89 | 3.24 | 0.8 |
| 14 | | W. Twitchell | 16.0 | 0.00 | 1971 | PHI | 6 | 1 | 0 | 1.000 | 1 | 15 | 0 | 0 | 0 | 8 | 0 | 4 | 1 | 10 | 1 | 2 | 0 | 69 | 0 | 8.44 | 5.63 | 1.50 | 0.56 | 21.7 | 14.5 | 1.13 | .167 | 2.25 | 0 | 3.45 | 99 | 4.50 | 0.1 |
| 15 |  | B. McClure | 15.1 | 0.00 | 1975 |  KCR | 12 | 1 | 0 | 1.000 | 0 | 15 | 0 | 0 | 1 | 4 | 0 | 0 | 0 | 14 | 0 | 4 | 2 | 66 | 0 | 8.80 | 8.22 | 1.07 | 0.00 | 22.7 | 21.2 | 1.17 | .108 | 0.00 | 0 | 3.36 | 90 | 2.35 | 0.6 |
| 16 |  | V. Palacios | 15.0 | 0.00 | 1990 |  PIT | 7 | 0 | 0 | 0 | 8 | 0 | 0 | 3 | 4 | 0 | 0 | 0 | 2 | 0 | 4 | 0 | 50 | 2 | 4.80 | 1.20 | 4.00 | 0.00 | 16.0 | 4.0 | 0.40 | .100 | 0.00 | 0 | 2.13 | 57 | 2.40 | 2.7 | |
| 17 |  | D. Ford | 15.0 | 0.00 | 1978 |  BAL | 2 | 1 | 0 | 1.000 | 1 | 5 | 0 | 0 | 0 | 10 | 0 | 0 | 0 | 2 | 0 | 1 | 0 | 53 | 0 | 3.00 | 1.20 | 2.50 | 0.00 | 9.4 | 3.8 | 0.80 | .217 | 0.00 | 0 | 2.31 | 62 | 6.00 | 2.4 |
| 18 |  | J. Hernandez | 14.1 | 0.00 | 1991 |  SDP | 9 | 0 | 0 | 0 | 9 | 0 | 0 | 2 | 8 | 0 | 1 | 0 | 5 | 0 | 7 | 0 | 56 | 2 | 5.65 | 3.14 | 1.80 | 0.00 | 16.1 | 8.9 | 0.91 | .190 | 0.63 | 0 | 2.64 | 68 | 5.02 | 1.9 | |
| 19 |  | E. Scribner | 14.0 | 0.00 | 2016 |  SEA | 12 | 0 | 0 | 0 | 15 | 0 | 0 | 0 | 5 | 0 | 0 | 0 | 2 | 1 | 0 | 1 | 49 | 0 | 9.64 | 1.29 | 7.50 | 0.00 | 30.6 | 4.1 | 0.50 | .161 | 0.00 | 0 | 1.64 | 39 | 3.21 | 4 | |
| 20 |  | M. Hinckley | 13.2 | 0.00 | 2008 |  WSH | 14 | 0 | 0 | 0 | 9 | 0 | 0 | 0 | 8 | 0 | 1 | 0 | 3 | 1 | 2 | 0 | 49 | 0 | 5.93 | 1.98 | 3.00 | 0.00 | 18.4 | 6.1 | 0.80 | .222 | 0.66 | 0 | 2.68 | 62 | 5.27 | 2.5 | |
| 21 |  | H. Strickland | 13.1 | 0.00 | 2025 |  LAA | 11 | 1 | 0 | 1.000 | 0 | 6 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 4 | 0 | 1 | 0 | 50 | 0 | 4.05 | 2.70 | 1.50 | 0.00 | 12.0 | 8.0 | 0.75 | .150 | 0.00 | 0 | 3.07 | 73 | 4.05 | 1.6 |
| 22 |  | K. Castro | 13.1 | 0.00 | 2021 |  SFG | 10 | 1 | 1 | .500 | 0 | 13 | 0 | 0 | 0 | 13 | 0 | 1 | 0 | 4 | 0 | 4 | 1 | 56 | 0 | 8.78 | 2.70 | 3.25 | 0.00 | 23.2 | 7.1 | 1.27 | .333 | 0.68 | 0 | 2.11 | 52 | 8.78 | 3 |
| 23 |  | C. Puleo | 13.1 | 0.00 | 1981 |  NYM | 4 | 0 | 0 | 1 | 8 | 0 | 0 | 0 | 8 | 0 | 1 | 0 | 8 | 0 | 2 | 2 | 53 | 1 | 5.40 | 5.40 | 1.00 | 0.00 | 15.1 | 15.1 | 1.20 | .216 | 0.68 | 0 | 3.20 | 94 | 5.40 | 0.3 | |
| 24 | | K. Brett | 13.1 | 0.00 | 1980 | KCR | 8 | 0 | 0 | 0 | 4 | 0 | 0 | 1 | 8 | 0 | 0 | 0 | 5 | 1 | 3 | 0 | 54 | 0 | 2.70 | 3.38 | 0.80 | 0.00 | 7.4 | 9.3 | 0.98 | .182 | 0.00 | 0 | 3.49 | 89 | 5.40 | 0.7 | |
| 25 | | E. Sabrowski | 12.2 | 0.00 | 2024 |  CLE | 8 | 0 | 0 | 0 | 19 | 0 | 0 | 1 | 6 | 0 | 0 | 0 | 4 | 0 | 4 | 0 | 47 | 1 | 13.50 | 2.84 | 4.75 | 0.00 | 40.4 | 8.5 | 0.79 | .250 | 0.00 | 0 | 1.11 | 27 | 4.26 | 4.2 | |
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