Carson Palmer suffers concussion as Cardinals fall to 1-3

Arizona Cardinals quarterback Carson Palmer left Sunday's game against the Los Angeles Rams after suffering what was later determined to be a concussion on a fourth-quarter sack.

Cardinals coach Bruce Arians confirmed after the game Palmer was placed in the concussion protocol. With a Thursday game against the San Francisco 49ers looming, Arians said the team would be cautious with Palmer.

Palmer's head hit the ground hard on a third-down sack by Aaron Donald and Eugene Sims. He later went to the locker room.

Drew Stanton stepped in at quarterback but could not lead the Cardinals past a 17-13 deficit. Arizona fell to 1-3 on the season.

Before leaving the game, Palmer completed 23 of 36 passes for 288 yards, a touchdown and an interception.

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