Still, Warner's availability to practice this week or play Sunday at Tennessee will depend on how he does in the mandatory "baseline test" of his cognitive functions. Whisenhunt says the test probably will be administered Tuesday.
"We are obviously optimistic that there won't be any issues with that whatsoever," the coach said Monday.
"We talked about the game," Whisenhunt said. "We talked about this week's opponent, potential plays. He seemed very upbeat and alert, so that was a good sign."
Warner's head slammed into the turf on a hit from Rams safety O.J. Atogwe during the second quarter. Warner stayed in the game to complete the touchdown drive that put Arizona up 21-3, then left for good.
Whisenhunt says that Warner had concussion-like symptoms and wouldn't have gone back in the game.
"We didn't know what it was for sure," Whisenhunt said. "He still played and seemed to be fine, but we said, 'Let's make sure,' right before the half and took him out. Certainly, we would not have put him back in."
"You always take it one day at a time, especially with a head injury," Warner said. "I feel pretty good today. I don't know if I feel 100 percent right now. So that's how I approach it. We're going to be safe, and we're going to make sure I am good to go before I get back out there. But I feel a lot better today than I did yesterday, and that's progress."
After the game Sunday, Warner said he went to team trainers right after the touchdown drive to tell them things "were a little unclear."
"Personally, I felt I could have played today," Warner said Sunday. "But it's just one of those things, one of those 'catch 22' situations where you want to play, you want to help your team win, but you also don't want to do anything dumb that's going to jeopardize you for the rest of the season."
Warner has sustained previous head injuries. As part of the recent Associated Press league-wide survey, Warner said he had four concussions in his career, two "minor" ones in the NFL, one in the Arena Football League and one non-football related while he was in college.
Whisenhunt said he pulled in the reins on the offense Sunday when Leinart went in the game.
"There were a lot of things that we didn't allow him to do because this was a team that was blitzing and selling out to try to stop us," the coach said. "I didn't want to put Matt in a position where we would potentially have a turnover or a negative play."
Leinart completed 10 of 14 passes for 74 yards.
"He missed some things," Whisenhunt said. "He threw one high. There were a couple of reads (that he missed), understandably. Not every quarterback is going to make every read."
The coach noted that the Cardinals lost the ball on a fumble by tight end Anthony Becht and failed to convert on a third-and-1 situation.
"I think either one of those two drives, potentially, we would have scored a touchdown and we wouldn't be having any of these questions," Whisenhunt said.
Leinart acknowledged that he was a bit rusty.
"Honestly, I haven't played a significant game in two and a half years," he said. "It's been a while, so it feels good to be out there where we had to do a few things. Am I happy? I'm happy we won. You know obviously I'm going to get better, and when the opportunity comes, I'm going to keep making the most of it."
The Associated Press contributed to this report.