Arizona Cardinals quarterback Carson Palmer was taken to the locker room to examine an injury to his left arm in the second quarter of Sunday's game against the Los Angeles Rams in London.
Drew Stanton replaced Palmer on the field.
The Cardinals declared five minutes into the third quarter that Palmer will not return to the game.
Before the injury, Palmer was 10-for-18 for 122 yards and an interception as the Cardinals trailed the Rams 13-0.
