, who has tormented the USA in the World Cup qualifying, won't be available when Costa Rica faces the USA on Sept. 1. He suffered a torn ligament in his knee at the Gold Cup and
could be out for up to six months.
Campbell, who is under contract with Costa Rica, was injured in the Ticos' 1-1 draw against Canada.
"It is sad and difficult to have to
leave the national team," he said. "I gave it everything, as I always do. Now I have to think about my recovery to come back stronger than ever."
Campbell was signed by Arsenal at the age
of 18 but has spent five of his seasons on loan to clubs abroad. He played for Portugal's Sporting in 2015-16.
He scored twice off the bench in Costa Rica's 4-0 win over the USA in
November 2016 and had the insurance goal in the Ticos' 3-1 win in World Cup qualifying in 2013.
Campbell is the second player the Ticos have lost in recent weeks. Ronald Matarrita
needed surgery on his right fifth metatarsal after suffering a fracture playing for New York City FC.