| Closer | 1st in line | 2nd in line | Updated | Closer | 1st in line | 2nd in line | Updated | ||
| BAL | Givens | Fry | Wright Jr. | 9/17/18 | ATL | Minter | Venters | Winkler | 9/15/18 |
| BOS | Kimbrel | Wright | Brasier | 9/17/18 | MIA | *Steckenrider | Conley | Barraclough | 9/18/18 |
| NYY | Chapman | Betances | Robertson | 9/21/18 | NYM | Gsellman | Lugo | Swarzak | 9/21/18 |
| TB | *Romo | Alvarado | Roe | 9/21/18 | PHI | *Hunter | Neshek | Dominguez | 9/19/18 |
| TOR | Giles | Tepera | Clippard | 8/16/18 | WAS | *Doolittle | Holland | Miller | 9/12/18 |
| CHW | *Fry | Jones | Minaya | 9/20/18 | CHC | *Cishek | Wilson | Edwards | 9/21/18 |
| CLE | *Hand | Allen | Miller | 9/19/18 | CIN | Iglesias | Hughes | Hernandez | 7/30/18 |
| DET | Greene | Jimenez | Wilson | 9/4/18 | MIL | *Jeffress | Hader | Knebel | 9/18/18 |
| KC | Peralta | McCarthy | Hill | 9/4/18 | PIT | Vazquez | Crick | Rodriguez | 9/17/18 |
| MIN | *Hildenberger | Rogers | May | 8/30/18 | STL | Martinez | Hicks | Hudson | 9/10/18 |
| HOU | Osuna | Rondon | McHugh | 9/13/18 | ARI | *Hirano | Ziegler | Bradley | 9/19/18 |
| LAA | *Buttrey | Parker | Anderson | 9/17/18 | COL | Davis | Ottavino | Oh | 9/6/18 |
| OAK | Treinen | Familia | Rodney | 9/12/18 | LAD | Jansen | Maeda | Alexander | 9/10/18 |
| SEA | Diaz | Colome | Vincent | 9/2/18 | SD | Yates | Stammen | Strahm | 9/4/18 |
| TEX | Leclerc | Martin | Claudio | 9/5/18 | SF | Smith | Melancon | Strickland | 8/28/18 |
* = closer-by-committee
