Cardinals left tackle D.J. Humphries was ejected for making contact with an official with 9:18 remaining in the second quarter.
Humphries was taking a swipe at Seahawks linebacker Jordyn Brooks and instead hit an official in the head, knocking off his cap.
There were two other penalties on the play.
Cardinals quarterback Joshua Dobbs threw a pass intended for Michael Wilson that Devon Witherspoon intercepted in the end zone and returned 18 yards. Boye Mafe, though, hit Dobbs in the head, drawing a roughing the passer penalty, and Brooks was penalized for unnecessary roughness.
The penalties gave the Seahawks a first-and-goal at the 25, and Dobbs ran it in on the next play to give the Cardinals a 10-7 lead.
Kelvin Beachum has replaced Humphries at left tackle.