MLS
USA
| Referee | Games |  |  | Cards per game |
|---|
| Elijio Arreguin | 2 | 9 | 1 | 5.0 (4.5 / 0.5) | |
| Malik Badawi | 2 | 13 | 0 | 6.5 (6.5 / 0.0) | |
| Fotis Bazakos | 3 | 13 | 0 | 4.3 (4.3 / 0.0) | |
| Nabil Bensalah | 1 | 4 | 0 | 4.0 (4.0 / 0.0) | |
| Serhiy Boiko | 3 | 12 | 1 | 4.3 (4.0 / 0.3) | |
| Allen Chapman | 3 | 7 | 2 | 3.0 (2.3 / 0.7) | |
| Alexis Da Silva | 3 | 10 | 1 | 3.6 (3.3 / 0.3) | |
| Marcos de Oliveira | 2 | 6 | 0 | 3.0 (3.0 / 0.0) | |
| Sergii Demianchuk | 2 | 7 | 0 | 3.5 (3.5 / 0.0) | |
| Joe Dickerson | 2 | 8 | 1 | 4.5 (4.0 / 0.5) | |
| Filip Dujic | 3 | 12 | 1 | 4.3 (4.0 / 0.3) | |
| Ismail Elfath | 3 | 14 | 1 | 5.0 (4.7 / 0.3) | |
| Ricardo Fierro | 2 | 7 | 0 | 3.5 (3.5 / 0.0) | |
| Drew Fischer | 4 | 14 | 1 | 3.8 (3.5 / 0.3) | |
| Timothy Ford | 2 | 7 | 0 | 3.5 (3.5 / 0.0) | |
| Jon Freemon | 3 | 13 | 2 | 5.0 (4.3 / 0.7) | |
| Guido Gonzales Jr. | 3 | 12 | 2 | 4.7 (4.0 / 0.7) | |
| Lorenzo Hernandez | 2 | 11 | 1 | 6.0 (5.5 / 0.5) | |
| Pierre-Luc Lauziere | 3 | 9 | 0 | 3.0 (3.0 / 0.0) | |
| Jair Marrufo | 3 | 7 | 1 | 2.6 (2.3 / 0.3) | |
| Rosendo Mendoza | 4 | 12 | 2 | 3.5 (3.0 / 0.5) | |
| Ricardo Montero | 2 | 11 | 0 | 5.5 (5.5 / 0.0) | |
| Chris Penso | 3 | 12 | 1 | 4.3 (4.0 / 0.3) | |
| Tori Penso | 3 | 11 | 0 | 3.7 (3.7 / 0.0) | |
| Victor Rivas | 4 | 20 | 1 | 5.3 (5.0 / 0.3) | |
| Brandon Stevis | 1 | 4 | 0 | 4.0 (4.0 / 0.0) | |
| Rubiel Vazquez | 3 | 14 | 1 | 5.0 (4.7 / 0.3) | |
| Armando Villareal | 3 | 12 | 0 | 4.0 (4.0 / 0.0) | |
England