US right back Fabian Johnson leaves World Cup game vs Belgium with apparent hamstring injury

U.S. right back Fabian Johnson has left the World Cup game against Belgium in the first half after appearing to strain a hamstring.

Johnson was chasing a ball in the 31st minute Tuesday when he pulled up and sat down on the field. He was replaced by 20-year-old DeAndre Yedlin, one of coach Jurgen Klinsmann's surprise picks for the U.S. roster.

Forward Jozy Altidore injured a hamstring in the Americans' opener against Ghana on June 16 and hasn't played since. Klinsmann said he was available for Tuesday's game off the bench.