The third-year quarterback, who made four unimpressive starts as a rookie, will be thrown into the teeth of the fierce Seattle defense Sunday night.
It's a tough spot for someone who never took a snap as Arizona's No. 3 quarterback last year, then was released in favor of rookie Logan Thomas at the end of this preseason.
When Carson Palmer went down with a season-ending knee injury, the Cardinals signed Lindley off the San Diego practice squad. And when Palmer's replacement, Drew Stanton, sprained his right knee Thursday night in St. Louis, Arians turned to Lindley rather than Thomas to finish the game.
''He was calm as a cucumber out there,'' Arians said before Wednesday's practice.
The stakes on Sunday night are high.
Arizona (11-3) is the only NFC team to have clinched a spot in the playoffs. A victory over the Seahawks (10-4) would ensure the NFC's No. 1 seed, guaranteeing that the Cardinals would play at home throughout the playoffs, including the Super Bowl, since it's being played in Arizona.
A Seattle victory would give the reigning Super Bowl champs a tie for first in the NFC West, and they would have the tiebreaker by virtue of two wins over the Cardinals. Arizona probably would be relegated to a wild card berth and a road game in the first round.
Largely because the Cardinals are down to a third-string, maybe fourth-string, quarterback, oddsmakers have made Seattle an eight-point favorite on the road.
''I think it's all about money in Vegas,'' Lindley said. ''They're just dealing with facts. They aren't worrying about the people and the intangibles.''
Arizona drafted Lindley in the sixth round out of San Diego State in 2012. With the Cardinals' season circling the drain, then-coach Ken Whisenhunt made the rookie the starter with the team in the midst of losing 11 of its last 12 games.
The results weren't good. Lindley completed 52 percent of his passes for 752 yards and zero touchdowns. He was intercepted seven times. His 181 passes attempted - including 10 last week - are the most in NFL history without a touchdown.
But this is a far better team than the one two years ago, and Lindley insists he's a different quarterback.
''It's night and day,'' he said. ''The amount I've learned and not only grown as a person in two years, but from these guys - B.A. (Arians), from Carson, from Drew. I'm a totally different person and totally different player from that point.''
He said the biggest difference between now and then is ''knowing what's coming.''
''Obviously the first time out there before, it's new, and you don't know exactly what's going to happen,'' Lindley said. ''But now, through experience, through seeing how these guys Drew and Carson prepare, how Philip (Rivers) prepares out in San Diego, I just feel a lot more ready at this point.''
Lindley said it's ''50-50'' as to whether his playing time in 2012 did more harm than good.
''The biggest thing is if you don't let it affect your confidence too much,'' he said, ''anything's a learning experience.''
He said he got through it with the support of his family and his faith.
''It's just trusting in whatever the plan will be,'' Lindley said. ''Just waiting for this opportunity. I feel extremely blessed and excited that it's here.''
Arians dismisses the term ''game manager.'' He said the Cardinals won't scale back their style just because of the quarterback. He has, however, tailored a game plan to Lindley's skills.
''There are some things in the offense he likes to throw,'' Arians said. ''Each guy's got two or three things that they like a little bit more than the others.''
Asked where Lindley concerns him, Arians responded, ''He really doesn't.''
''He's a meticulous preparation guy,'' the coach said. ''The dynamics between us - I've bounced things off him. I trust him as far as his mental makeup to the game.''
To keep the Seahawks guessing, Arians has developed a package for Thomas and says he might use both quarterbacks.
''It's tough to find at this level, a guy that you want to pour it onto the field for,'' Lindley said, ''and B.A. gets his guys to play their best for him.''
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