Since 1960, 47 pitchers are tied for the best ERA by a rookie relief pitcher, with an ERA of 0.00. The first three are Austin Pope, Roki Sasaki and Hunter Barco this season.
| NAME | ERA | SEASON | TM | G | W | L | W% | GS | SO | CG | SHO | SV | IP | H | ER | R | HR | BB | HBP | GF | IBB | TBF | WP | K/9 | BB/9 | K/BB | HR/9 | K% | BB% | WHIP | BABIP | RA | H/9 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | A. Pope | 0.00 | 2025 |  AZ | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2.0 | 2 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 9 | 0 | 4.50 | 4.50 | 1.00 | 0.00 | 11.1 | 11.1 | 1.50 | .286 | 0.00 | 9.00 | |
| 2 |  | R. Sasaki | 0.00 | 2025 |  LAD | 2 | 0 | 0 | 0 | 4 | 0 | 0 | 0 | 2.0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7 | 0 | 18.00 | 0.00 | 0.00 | 57.1 | 0.0 | 0.50 | .333 | 0.00 | 4.50 | ||
| 3 | | H. Barco | 0.00 | 2025 |  PIT | 2 | 1 | 0 | 1.000 | 0 | 3 | 0 | 0 | 0 | 3.0 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 12 | 0 | 9.00 | 0.00 | 0.00 | 25.0 | 0.0 | 1.00 | .333 | 0.00 | 9.00 | |
| 4 | | J. Espada | 0.00 | 2025 |  BAL | 1 | 0 | 0 | 0 | 4 | 0 | 0 | 0 | 3.0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 9 | 0 | 12.00 | 0.00 | 0.00 | 44.4 | 0.0 | 0.33 | .200 | 0.00 | 3.00 | ||
| 5 | | D. Hamel | 0.00 | 2025 |  NYM | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 3 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 6 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 3.00 | .600 | 0.00 | 27.00 | ||
| 6 | | L. Davidson | 0.00 | 2025 |  LAA | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 3 | 0 | 9.00 | 0.00 | 0.00 | 33.3 | 0.0 | 0.00 | .000 | 0.00 | 0.00 | ||
| 7 | | G. Acton | 0.00 | 2025 |  TBR | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 2 | 0 | 1 | 0 | 5 | 1 | 0.00 | 18.00 | 0.00 | 0.00 | 0.0 | 40.0 | 2.00 | .000 | 0.00 | 0.00 | |
| 8 | | N. Raquet | 0.00 | 2025 |  STL | 2 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2.0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 7 | 0 | 4.50 | 4.50 | 1.00 | 0.00 | 14.3 | 14.3 | 0.50 | .000 | 0.00 | 0.00 | |
| 9 | | C. Roa | 0.00 | 2025 |  MIA | 2 | 0 | 0 | 0 | 3 | 0 | 0 | 0 | 3.0 | 1 | 0 | 0 | 0 | 3 | 0 | 1 | 0 | 12 | 0 | 9.00 | 9.00 | 1.00 | 0.00 | 25.0 | 25.0 | 1.33 | .167 | 0.00 | 3.00 | |
| 10 | | R. Fitzgerald | 0.00 | 2025 |  MIN | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2.0 | 2 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 8 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 1.00 | .250 | 0.00 | 9.00 | ||
| 11 | | N. Kavadas | 0.00 | 2025 | LAA | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1.2 | 3 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 9 | 0 | 5.40 | 5.40 | 1.00 | 0.00 | 11.1 | 11.1 | 2.40 | .429 | 0.00 | 16.20 | |
| 12 | | A. Seigler | 0.00 | 2025 |  MIL | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 4 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 1.00 | .250 | 0.00 | 9.00 | ||
| 13 | | K. Teng | 0.00 | 2025 |  SFG | 1 | 1 | 0 | 1.000 | 0 | 4 | 0 | 0 | 0 | 5.0 | 3 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 18 | 0 | 7.20 | 1.80 | 4.00 | 0.00 | 22.2 | 5.6 | 0.80 | .231 | 0.00 | 5.40 |
| 14 | | D. Nikhazy | 0.00 | 2025 |  CLE | 1 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 3 | 0 | 18.00 | 0.00 | 0.00 | 66.7 | 0.0 | 0.00 | .000 | 0.00 | 0.00 | ||
| 15 | | L. Vázquez | 0.00 | 2025 | BAL | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4.1 | 3 | 0 | 0 | 0 | 1 | 0 | 4 | 0 | 14 | 0 | 0.00 | 2.08 | 0.00 | 0.00 | 0.0 | 7.1 | 0.92 | .231 | 0.00 | 6.23 | |
| 16 | | C. Petty | 0.00 | 2025 |  CIN | 1 | 0 | 1 | .000 | 0 | 0 | 0 | 0 | 0 | 0.2 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 4 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 1.50 | .333 | 13.50 | 13.50 | |
| 17 | | J. Young | 0.00 | 2025 | NYM | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.1 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 3 | 0 | 0.00 | 27.00 | 0.00 | 0.00 | 0.0 | 33.3 | 6.00 | .500 | 0.00 | 27.00 | |
| 18 | | C. Montes De Oca | 0.00 | 2025 | AZ | 1 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 2.2 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 9 | 0 | 6.75 | 3.38 | 2.00 | 0.00 | 22.2 | 11.1 | 0.38 | .000 | 0.00 | 0.00 | |
| 19 | | W. Wilson | 0.00 | 2025 |  PHI | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3.0 | 3 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 12 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 1.00 | .250 | 0.00 | 9.00 | ||
| 20 | | E. Lucas | 0.00 | 2025 |  TOR | 1 | 1 | 0 | 1.000 | 0 | 3 | 0 | 0 | 0 | 4.2 | 4 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 18 | 0 | 5.79 | 1.93 | 3.00 | 0.00 | 16.7 | 5.6 | 1.07 | .286 | 0.00 | 7.71 |
| 21 | | C. Salazar | 0.00 | 2025 |  HOU | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 4 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 0.00 | .000 | 0.00 | 0.00 | ||
| 22 | | W. MacIver | 0.00 | 2025 |  ATH | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2.0 | 4 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 10 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 2.00 | .400 | 0.00 | 18.00 | ||
| 23 | | L. Rivas | 0.00 | 2025 |  SEA | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 3 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 6 | 0 | 0.00 | 9.00 | 0.00 | 0.00 | 0.0 | 16.7 | 4.00 | .600 | 0.00 | 27.00 | |
| 24 | | J. Amaya | 0.00 | 2025 |  CWS | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 3 | 0 | 0.00 | 0.00 | 0.00 | 0.0 | 0.0 | 0.00 | .000 | 0.00 | 0.00 | ||
| 25 | | M. McGreevy | 0.00 | 2025 | STL | 1 | 1 | 0 | 1.000 | 0 | 5 | 0 | 0 | 0 | 5.2 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 20 | 0 | 7.94 | 1.59 | 5.00 | 0.00 | 25.0 | 5.0 | 0.35 | .077 | 0.00 | 1.59 |
StatMuse has game-level data for ERA going back to the 1901 season.
Some of the information used here was obtained free of charge from Retrosheet.
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