West Ham United manager Slaven Bilic has confirmed Manuel Lanzini will be out for up to five weeks through injury.
Last month, Lanzini, 23, pulled out of Argentina's squad for the Olympics because of a knee problem.
Having returned to his club, the Hammers have confirmed they will be without the attacker for the start of the 2016-17 season.
Bilic said: "Unfortunately for us, Manuel Lanzini's injury is a blow. It's not a big injury but he can't play for the next four or five weeks."
Lanzini signed for West Ham from Al Jazira last summer and he went on to score six Premier League goals in 26 appearances in 2015-16.
Bilic's side open their Premier League season at Chelsea on Aug. 15.