HOUSTON — Brian Ching will be sidelined for at least several weeks after hurting his left hamstring while playing for Major League Soccer's Houston Dynamo, an injury that could hamper the American forward's preparations for the World Cup.

Dynamo spokesman Lester Gretsch said Ching was re-evaluated by team doctors Friday, but no MRI was taken because of the Good Friday holiday. He says Ching will be out at minimum of a few weeks but the projected length of the layoff won't be known until early next week.

Ching left the Dynamo's home opener against Real Salt Lake on Thursday night because of the strain.

The 31-year-old from Hale'iwa made his national team debut in 2003 and has 11 goals in 44 international appearances. He was on the 2006 U.S. World Cup roster but didn't play during the tournament.

With Sochaux's Charlie Davies still sidelined because of severe injuries sustained in an October car crash, the U.S. is uncertain who will s tart at forward alongside Hull's Jozy Altidore. Ching and Colorado's Conor Casey have been competing to make the 23-man roster as forwards.

The U.S. team will gather in mid-May ahead of its World Cup opener against England on June 12. The Americans have exhibitions against the Czech Republic (May 25 at East Hartford, Conn.), Turkey (May 29 at Philadelphia) and Australia (June 5 at Roodepoort, South Africa) before meeting England in Rustenburg, South Africa.