There's a new name to add to the growing USMNT injury list ahead of World Cup qualifiers against Costa Rica and Mexico later this month.

US left back Fabian Johnson missed Hoffenheim's match on Saturday against Greuther Fürth with reported "muscular problems," according to one German outlet. The Bundesliga's official site pinpoints the injury at the "hip." Hoffenheim still won the road match 3-0.

No response yet from the club after a request from MLSsoccer.com seeking details.

Although the severity of Johnson's physical issue is still unclear, it could mean that the US may be without two potential starters at a position that does not feature much depth: left back. Club Tijuana's American left back Edgar Castillo is recovering from broken bones in his face.

The Johnson news only compounds the selection issues for USMNT manager Jurgen Klinsmann. News emerged Friday of a back injury for US captain and starting goalkeeper Tim Howard and goalscoring star Clint Dempsey is working his way back from a calf strain.

Klinsmann already knows he'll be without Landon Donovan, who has yet to rejoin the LA Galaxy. And another veteran, right back Steve Cherundolo, is out of action following a left knee procedure.

After a 2-1 loss at Honduras in the opener of the CONCACAF Hexagonal, the USMNT faces Costa Rica at Dick's Sporting Goods Park on March 22 and then face a daunting trip to the Estadio Azteca for a match-up against CONCACAF powers Mexico.