Lionel Messi remained at the heart of an injury scare only weeks before the World Cup after medical tests diagnosed him with muscle fatigue in his left hamstring, Inter Miami announced on Monday.

The Major League Soccer (MLS) club’s update provided no clear timetable for the Argentine superstar’s return after his abrupt exit from Miami’s 6-4 victory over Philadelphia in the 73rd minute on Sunday.

The 38-year-old icon for the defending World Cup champions grabbed the back of his left leg and asked to come off, but appeared to be walking normally as he made his exit to the changing room.

“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.”

That gave precious little indication about the status of the eight-time Ballon d’Or winner as Argentina prepares to defend the crown in a World Cup co-hosted by the United States, Canada and Mexico that kicks off June 11.