The midfielder sustained the injury with the U.S. national team in the first half of a 6-0 victory over Honduras on March 24. Lletget scored the opening goal of the contest, the first of his international career, before having to be substituted off after being fouled.
Initial reports were Lletget had only suffered a strain, but the Galaxy revealed Tuesday further testing by the club and U.S. Soccer determined a Lisfranc injury, which will require surgery.
The Galaxy have suffered multiple key losses to begin the season under new coach Curt Onalfo, with Giovani dos Santos, Gyasi Zardes, Ashley Cole and Robbie Rogers among those sidelined. The Galaxy, who have begun the campain with a win and two losses, next play April 1 in Vancouver against the Whitecaps.