Phoenix coach Ernie Merrick said Hernandez suffered the injury early on in Friday's 1-0 victory over Melbourne Heart at AAMI Park.
Hernandez played on but started complaining about aching pain after the match and was sent for X-rays in Sydney yesterday.
"He's fractured his scaphoid and is flying home today," Merrick said.
"He will have surgery in a couple of days and it is normally a six-week injury. He's pretty devastated because he wants to play at the World Cup [for Costa Rica next year]."
http://www.stuff.co.nz/dominion-post/sport/football/9566807/