The latest quarterback to audition is Ryan Lindley, a sixth-round pick in the 2012 draft who received his first NFL start against the Rams last Sunday.
Lindley, who completed 31-of-52 passes for 312 yards with four interceptions, had his struggles.
But according to Warner, who was a guest of Arizona Sports 620's Doug and Wolf Wednesday, he also had some very positive moments.
"I saw a lot of good things," Warner said. "I felt like, especially early in the game, things were really good."
Warner, who is an analyst for the NFL Network, said it appeared things "got away from" Lindley as the game wore on, and the pair of pick-sixes the QB threw certainly didn't help.
"But I was impressed; I thought he made some really good throws," Warner added. "Some tough reads or went to places where you might not expect a rookie to go and deliver the football well."
Warner said Lindley did make some of the classic rookie mistakes, but overall he was "really impressed" with the way the 23-year-old played.