Messi, 38, left Sunday’s 6-4 Major League Soccer victory over the Philadelphia Union in the 73rd minute after clutching the back of his thigh following a free kick.

“After undergoing further medical tests this Monday, the initial diagnosis indicates an overload associated with muscle fatigue in his left hamstring,” Inter Miami said in a statement.

“The timeline for his return to physical activity will depend on his clinical and functional progress,” it said.

Inter Miami coach Guillermo Hoyos had downplayed the issue after the match, saying Messi appeared fatigued after playing on a “heavy” pitch.

Major League Soccer is now pausing for the World Cup, which will be co-hosted by the US, Canada and Mexico from June 11 to July 19.

Argentina coach Lionel Scaloni included eight-times Ballon d’Or winner Messi in a provisional 55-man squad announced earlier this month, ahead of the defending champions’ opening match against Algeria in Kansas City on June 16.

Messi captained Argentina to their third World Cup title in Qatar in 2022 and is expected to lead the team again in what could be his sixth appearance at the tournament.