American winger Gio Reyna missed Borussia Dortmund's exhibition against Athletic Bilbao because of a thigh injury sustained during warmups.

Dortmund said the injury was slight and the 18-year-old was replaced by Goktan Gurpuz in the starting lineup for the 2-0 loss Satuday at St. Gallen, Switzerland.

Dortmund opens the Bundesliga season on Aug. 14 at home against Eintracht Frankfurt.

The U.S. starts World Cup qualifying on Sept. 2 at El Salvador.

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