After head coach Bruce Arians said he "has no idea" who will start on Sunday, Fox Sports Radio 910's Mike Jurecki reported Friday evening that backup quarterback Drew Stanton had passed all the tests necessary to get through the concussion protocol and has been cleared to play on Sunday.
The question will remain whether or not he got enough reps for Arians to be comfortable with Stanton starting.
Rookie Logan Thomas took first team reps this week as Stanton was recover from a concussion he received last week against the Denver Broncos and starter Carson Palmer recovered from the shoulder nerve injury that has sidelined him for every game except Week 1.
Arians said Stanton "would be in the mix" for Sunday if he passed his tests, which he now has done.
This doesn't answer the question completely, but it seems much less likely that the rookie Thomas will get his first NFL start. Palmer could still get the green light, but unless that changes it looks more likely Stanton will be the one under center.