Inter Miami, who are scheduled to open their MLS campaign on February 21st, said the two-time reigning league MVP sustained the injury during a preseason game last weekend against Barcelona Sporting Club in Ecuador, where he scored but was substituted in the second half.
Messi underwent additional medical tests that confirmed the diagnosis.
"His gradual return to training will depend on his clinical and functional progress in the coming days," Inter Miami said.
As a result of the injury, the friendly between Inter Miami and Ecuadorian club Independiente del Valle, scheduled to be played on Friday at Juan Ramon Loubriel Stadium in Puerto Rico, has been postponed to February 26th.