The Newly-signed Oakland Raiders running back Isaiah Crowell tore his Achilles tendon during a workout Tuesday and is lost for the season, a source told ESPN's Adam Schefter Wednesday.
Crowell will undergo season-ending surgery next week, the source said.
Crowell had signed a one-year deal worth up to $2.5 million, according to sources.
The injury is the latest blow to the Raiders' depth chart at running back. Last week, Marshawn Lynch indicated that he's done playing football. Doug Martin was the team's leading rusher last season, but he was a free agent.
The Raiders used the No.