| Most Unearned Runs Allowed | |||||||
|---|---|---|---|---|---|---|---|
| Player | Team | Year | Age | IP | R | ER | UER |
| Wes Blair | PR | 2017 | 30 | 217.1 | 171 | 138 | 33 |
| Josh Wilhelm | PR | 2015 | 37 | 223.2 | 144 | 112 | 32 |
| Robby Marsh | PR | 2021 | 25 | 231.1 | 116 | 84 | 32 |
| Je-myung Son | PIT | 2021 | 25 | 128.0 | 116 | 84 | 32 |
| Marlon Holmes | BH | 2019 | 27 | 176.2 | 142 | 111 | 31 |
| Al Griffin | PB | 2007 | 27 | 209.2 | 136 | 105 | 31 |
| Bart Blackwood | AT | 2019 | 29 | 187.1 | 151 | 120 | 31 |
| Rafael Acevedo | MWB | 2008 | 27 | 192.2 | 136 | 106 | 30 |
| Darrel Lott | TCVC | 2057 | 33 | 203.0 | 171 | 141 | 30 |
| Doug Olson | ?? | 2027 | 28 | 193.0 | 153 | 123 | 30 |
| Cy McDougle | PP | 2007 | 22 | 222.1 | 107 | 78 | 29 |
| Artie Gálvez | PB | 2021 | 29 | 204.0 | 126 | 98 | 28 |
| Arthur McDormand | BB | 2025 | 29 | 159.1 | 126 | 98 | 28 |
| Lonnie Carney | MWB | 2019 | 28 | 198.1 | 125 | 98 | 27 |
| Rafael Acevedo | Det | 2018 | 37 | 181.2 | 148 | 122 | 26 |
| Jayson Cole | NYG | 2013 | 23 | 215.0 | 117 | 91 | 26 |
| Eldon Alexander | MWB | 2008 | 27 | 242.1 | 160 | 134 | 26 |
| Tom Herrick | PIT | 2021 | 26 | 208.1 | 122 | 96 | 26 |
| Shawn Johnston | SB | 2022 | 26 | 206.0 | 127 | 101 | 26 |
| Carlos Román | TCVC | 2007 | 26 | 206.0 | 133 | 108 | 25 |