TEMPE, Ariz. » The Arizona Cardinals won’t have Carson Palmer when they face the San Francisco 49ers on Thursday night.

Coach Bruce Arians said today the quarterback remains in the concussion protocol and has not been cleared to play. Arians said Palmer would not make the trip.

“Carson’s made great progress, but there’s no way I’m going to take any chances with him,” Arians said. “He argued with me a little bit, but he has not cleared.”

Backup Drew Stanton will make the 13th start of his 10-year NFL career, but first since 2014. He went 5-3 as a starter that year when Palmer went down with shoulder and knee injuries.

Arians said he is “very optimistic” Palmer will be back for the Cardinals’ next game, a Monday night matchup at home against the New York Jets on Oct. 17.

Palmer was injured when his head slammed to the turf on a sack by Aaron Donald late in Arizona’s 17-13 loss to the Los Angeles Rams on Sunday.

The loss of the 36-year-old quarterback is a big blow to a struggling team that entered the season with the highest of expectations, but has sputtered to a 1-3 start.

Arizona is 31-13 with Palmer at quarterback.

Stanton signed a two-year contract to return to the Cardinals in the offseason. He has been with Arians since the coach’s days with the Indianapolis Colts. Stanton was a backup for the Detroit Lions for three seasons.

Stanton has appeared in 30 games, completing 54 percent of his passes for 3,021 yards and 12 touchdowns with 18 interceptions.

In 2014, the former Michigan State quarterback completed 55 percent of his passes for 1,711 yards and seven TDs with five interceptions before he went down with a season-ending knee injury. He was intercepted twice, one on a desperation pass as the game ended, in relief of Palmer on Sunday.

Stanton might best be remembered for his sideline gyrations during Andre Ellington’s 48-yard touchdown run that sealed a victory at Seattle last season.

Zac Dysert was promoted from the practice squad this week to be the backup to Stanton.

“He’s got about six weeks in. He’s a very bright guy,” Arians said. “He has a package he knows very well and is very comfortable with and we’ll use that package if we have to use it.”

Dysert was a seventh-round draft pick of Denver out of Miami (Ohio) in 2013. He was the Broncos’ No. 3 quarterback in 2013 and was on the Denver practice squad in 2014. He spent time with Chicago, Houston, Buffalo and Miami, but never was on the teams’ active roster. He has not taken a snap in an NFL game.

Arians said tight end Darren Fells (shoulder) and defensive tackle Ed Stinson (toe) also would not make the trip.

The Cardinals placed running back Chris Johnson (hernia) on injured reserve Tuesday. That moved Ellington to the No. 2 running back position behind David Johnson. Arians said Ellington would relinquish his role as kickoff returner, with Brittan Golden, also just up from the practice squad, taking his place.