The Kings confirmed Voynov's injury and surgery Wednesday.
Voynov has been suspended for the past 70 games following his arrest on domestic violence charges. The two-time Stanley Cup champion is allowed to work out at the Kings' training complex without his teammates during his suspension.
Voynov apparently was injured during Los Angeles' lengthy road trip, which ended Monday. The Kings didn't know any other details about Voynov's condition, but a torn Achilles tendon typically requires several months of rehabilitation.
Voynov's trial was postponed again Wednesday, moving from April 21 to July 6, according to the Los Angeles Times. Voynov and his wife appeared in court together.