Switzerland's soccer federation says midfielder Granit Xhaka injured his left knee in a training session and will need an MRI scan.

Xhaka's injury scare Thursday comes 18 days before Switzerland's opening World Cup game against Brazil.

He was helped away limping after being hurt in a challenge with teammate Valon Behrami during practice on a rain-soaked pitch Thursday.

The federation says Xhaka was treated by team doctors at their hotel and did not need to go to a hospital.

The 25-year-old Arsenal midfielder is an expected starter against Brazil, on June 17 in Rostov. The group also includes Serbia and Costa Rica.

Switzerland's first World Cup warm-up game is against Spain on Sunday in Villarreal.