MLS
USA
| Referee | Games |  |  | Cards per game |
|---|
| Elijio Arreguin | 1 | 3 | 0 | 3.0 (3.0 / 0.0) | |
| Malik Badawi | 7 | 26 | 0 | 3.7 (3.7 / 0.0) | |
| Fotis Bazakos | 6 | 27 | 1 | 4.7 (4.5 / 0.2) | |
| Serhiy Boiko | 9 | 40 | 3 | 4.7 (4.4 / 0.3) | |
| Allen Chapman | 8 | 20 | 1 | 2.6 (2.5 / 0.1) | |
| Alexis Da Silva | 7 | 27 | 1 | 4.0 (3.9 / 0.1) | |
| Marcos de Oliveira | 7 | 27 | 0 | 3.9 (3.9 / 0.0) | |
| Sergii Demianchuk | 4 | 19 | 1 | 5.1 (4.8 / 0.3) | |
| Joe Dickerson | 6 | 23 | 2 | 4.1 (3.8 / 0.3) | |
| Filip Dujic | 9 | 36 | 1 | 4.1 (4.0 / 0.1) | |
| Ricardo Fierro | 6 | 26 | 2 | 4.6 (4.3 / 0.3) | |
| Drew Fischer | 8 | 26 | 0 | 3.3 (3.3 / 0.0) | |
| Jon Freemon | 6 | 34 | 1 | 5.9 (5.7 / 0.2) | |
| Guido Gonzales Jr. | 6 | 28 | 0 | 4.7 (4.7 / 0.0) | |
| Guido Gonzales Jr. | 2 | 6 | 1 | 3.5 (3.0 / 0.5) | |
| Jorge Gonzalez | 1 | 1 | 0 | 1.0 (1.0 / 0.0) | |
| Lorenzo Hernandez | 4 | 12 | 0 | 3.0 (3.0 / 0.0) | |
| Ekaterina Koroleva | 1 | 6 | 0 | 6.0 (6.0 / 0.0) | |
| Pierre-Luc Lauziere | 8 | 39 | 2 | 5.2 (4.9 / 0.3) | |
| Jair Marrufo | 6 | 17 | 1 | 3.0 (2.8 / 0.2) | |
| Rosendo Mendoza | 8 | 46 | 2 | 6.1 (5.8 / 0.3) | |
| Abdou Ndiaye | 1 | 6 | 0 | 6.0 (6.0 / 0.0) | |
| Ismir Pekmic | 6 | 30 | 0 | 5.0 (5.0 / 0.0) | |
| Tori Penso | 7 | 26 | 1 | 3.8 (3.7 / 0.1) | |
| Chris Penso | 7 | 37 | 1 | 5.4 (5.3 / 0.1) | |
| Victor Rivas | 7 | 31 | 3 | 4.8 (4.4 / 0.4) | |
| Lukasz Szpala | 6 | 22 | 0 | 3.7 (3.7 / 0.0) | |
| Rubiel Vazquez | 7 | 26 | 0 | 3.7 (3.7 / 0.0) | |
| Armando Villareal | 3 | 12 | 1 | 4.3 (4.0 / 0.3) | |
Germany
