Arians earlier said he'd play Thomas for at least the first half. But that was before Thomas failed to inspire confidence at Wednesday's practice.
Thomas has appeared in two games, completing 1 of 9 throws. Starter
Arizona remains a 6-point underdog Sunday.
After earlier saying
Thomas has appeared in two games, completing 1 of 9 passes. That completion was an 81-yard touchdown to running back Andre Ellington.
Quarterback Drew Stanton (knee) isn't expected to be ready until the playoffs, so Lindley is the only option behind Thomas. Lindley has zero touchdowns and eight interceptions in 225 career pass attempts. Arizona has not scored a touchdown in its past two games.
A 6-6, 250-pounder out of Virginia Tech, Thomas had a "shaky" start to Wednesday's practice before finishing "pretty strong," according to Arians.
Arizona is a 6-point underdog Sunday. The line opened at 4.5 before bettors pounced on the 49ers.
Despite their offensive struggles, the Cardinals can win the NFC West with a victory and a Seattle loss to the Rams.
"He's worked, fundamentally, extremely hard and gotten much better," Arians said. "But putting those fundamentals to use in the offense, that's two totally different things."
Thomas has just three days of practice before facing the 49ers in a game that has the possibility of landing his team with a first-round bye with a win and help from other results.
"It wasn't the greatest, but as it went on, it got better and better," Thomas added. "It just comes with reps and comes with time."
The Cardinals are a 6-point underdog in San Francisco Sunday.
"He's going to practice some this week and we'll see how it goes," Arians said, via ESPN.com. "Do not plan on playing him this week unless it's absolutely necessary."
The Cardinals likely will enter the playoffs as a wildcard and play on the first weekend of January. Arizona needs Stanton (7 TDs, 5 INTs) to have a realistic chance of jumpstarting its offense.
"We'll go with Logan, and to be honest with you, I'll have a quick hook," Arians said. "I want to see what he's got with a week of preparation for our future, and into the playoffs what's the best thing for us."
With Drew Stanton (knee) still sidelined, coach Bruce Arians went with Lindley in a Week 16 home loss to Seattle. Lindley completed 18 of 44 passes for 216 yards with no touchdowns and one interception.
Thomas has appeared in two games this season. He has only completed one of nine attempts. His only completion resulted in an 81-yard touchdown pass to Andre Ellington.
Arizona is currently a 4 1/2-point underdog at San Francisco.
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