The Cardinals have ruled out Palmer (arm) for the rest of Sunday's contest versus the Rams in London, Kent Somers of The Arizona Republic reports.

EDGE Analysis

Palmer has a propensity for serious injuries, missing 33 of a possible 215 games since logging his first NFL start in Week 1 of the 2004 season. The severity of the current issue hasn't been revealed, but he held up his left arm while leaving the field, an unnatural move if there ever was one. While the Cardinals will clarify the ailment in due time, Drew Stanton will serve as the starting quarterback for as long as Palmer is sidelined.