Vela, Hernández left off Mexico Gold Cup roster by Martino.
Vela's omission was the biggest surprise. He leads Major League Soccer with 12 goals for Los Angeles FC.
"We spoke on the phone last week and he told me that his family and his club are his priorities and that*s why he prefers to stay aside," Martino said Wednesday. "The players have the right to come or not to come. In Carlos' case, he expressed the idea of not coming, and that*s a life decision not to play for Mexico."
Hernández is expecting his first child this summer, and Martino told Chicharito he should remain with his wife. Herrera said he is tired from a long season with Porto and is trying to define his future, and dos Santos does not have a club following his departure from Major League Soccer's LA Galaxy.
The most experienced players on the roster are goalkeeper Guillermo Ochoa and midfielder Andrés Guardado.
Hirving Lozano is on the roster after hurting a knee while with PSV Eindhoven in the Netherlands, but it is not clear whether he will recover ahead of Mexico's opener against Cuba on June 15 at Pasadena, California. El Tri also plays Canada four days later at Denver and Martinique on June 23 at Charlotte, North Carolina.
Defenders: Edson Álvarez (America), Néstor Araujo (Celta de Vigo, Spain), Jesús Gallardo (Monterrey), Miguel Layún (Monterrey), César Montes (Monterrey), Héctor Moreno (Real Sociedad, Spain), Fernando Navarro (Leon), Diego Reyes (Leganes, Spain), Luis Rodriguez (Tigres), Carlos Salcedo (Tigres), Jorge Sánchez (America)
Midfielders: Uriel Antuna (LA Galaxy), Jonathan dos Santos (LA Galaxy, MLS), Andrés Guardado (Betis, Spain), Érick Gutiérrez (PSV Eindhoven, Netherlands), Hirving Lozano (PSV Eindhoven, Netherlands), Luis Montes (Leon), Orbelin Pineda (Cruz Azul), Carlos Rodríguez (Monterrey), Iván Rodríguez (Leon)