The move snapped Warner's consecutive starts streak at 41 straight games, and he wound up watching from the sideline wearing sweats as Matt Leinart started in his place in a 20-17 loss to Tennessee.
"Whatever you want to call it, it feels like a light sensitivity or my eyes just aren't quite adjusted right. That was the one symptom," Warner said after the game. "I had some tightness in my neck all week, so I think we were trying to gauge whether what I was feeling was coming from the issues in my neck or whether it was an issue with my head."
Warner left last week's win at St. Louis after he hit his head against the turf. He had been listed as questionable and practiced all week. The 38-year-old quarterback counted that as his fifth concussion by his own tally.
He said he woke up Sunday and the soreness in his neck was gone. But he didn't feel what he called "perfect." He warmed up and threw balls on the field before Whisenhunt declared him inactive. Brian St. Pierre backed up Leinart, and the Cardinals did not list an emergency third quarterback.
"If we could've pinpointed it and believed that it was just muscular and in the neck, then I probably would've played. But we couldn't do that and for our comfort level, we decided not to go," Warner said.
Whisenhunt said Warner had been improving during the week. The sensitivity in the quarterback's eyes leads back to the question of whether or not the problem was concussion-related.
"We erred to the side of caution," Warner said.
That gave Leinart his first start since Oct. 7, 2007. He threw for 220 yards and helped the Cardinals score 14 straight points to take a 17-13 lead in the fourth quarter. But the Cardinals finished with 292 yards of offense, snapping three straight games with at least 400 yards.
"Matt played pretty well," Warner said. "I thought the whole team played well. You give yourself a chance on the road against a good football team to win. ... They made a great play at the end of the game to win, but this is what the NFL is."