The Arizona Cardinals have looked like a completely different team from the one that reached last season’s NFC Championship Game, and things might not get better any time soon. The team will visit the San Francisco 49ers on “Thursday Night Football” in Week 5, and it appears Arizona will be without Carson Palmer.

The starting quarterback left Sunday’s game against the Los Angeles Rams when he was evaluated for a concussion. Backup Drew Stanton was intercepted twice in relief of Palmer as the Cardinals went on to lose 17-13 at home.

With just three days in between games, Palmer likely won’t play in San Francisco. Cardinals coach Bruce Arians told reporters on Sunday that the team will be “very, very careful” with the quarterback.

Palmer didn’t leave Sunday’s game until the fourth quarter, and the Cardinals had been struggling even with their starter in the game. Arizona suffered their third loss in four games, falling two games behind the Rams and Seattle Seahawks for first place in the division.

On their way to a 13-3 record last season, Arizona ranked first in total offense, totaling over 408 yards per game. But aside from a 40-point outburst against the Tampa Bay Buccaneers in Week 2, the unit has vastly underachieved in 2016. The Cardinals have failed to score more than 21 points in all three of their losses, and Palmer’s 81.9 passer rating is his lowest since 2013. He was picked off four times in Arizona’s 33-18 loss to the Buffalo Bills in Week 3.

It will only get more difficult for the Cardinals to score with Stanton at the helm. Though perhaps he won’t be as bad as he was on Sunday, Stanton has been a career backup for a reason. He has a career passer rating of 66.5, and he posted a 78.7 passer rating in 2014 when he was forced to start half the season.

Drew Stanton Arizona Cardinals Drew Stanton threw two interceptions in the fourth quarter against the Los Angeles Rams at University of Phoenix Stadium on Oct. 2, 2016 in Glendale, Arizona. Photo: Getty

Stanton does have weapons that weren’t at his disposal two years ago. Running back David Johnson is among the best playmakers in the league, and he’s totaled 510 yards from scrimmage with three touchdowns this season. Larry Fitzgerald is still productive at 33 years old, but he averaged less than 40 receiving yards per game when Stanton started two years ago.

Despite their struggles and the injury to Palmer, Arizona is favored on the road. The San Francisco 49ers are also 1-3, and they are 2.5-point underdogs at Las Vegas and online sportsbooks, via OddsShark. After shutting out the Rams in the season opener, the 49ers have lost three straight games by a combined 45 points.

Blaine Gabbert continues to play like he shouldn’t be an NFL starting quarterback. His 73.1 passer rating ranks 30th out of 32 starters in 2016, and his career record as a starter sits at 9-30.

With two bad signal callers going head-to-head on short rest, Thursday’s game could get ugly fast. The over/under of 42 is one of the lowest on the season, and points could be hard to come by.

San Francisco isn’t a playoff contender, but the rest of the NFL might be learning that Arizona won’t compete for a playoff berth either. The 49ers have a chance to keep Thursday’s game close, and they could even pull out a victory in a low-scoring affair.

Prediction: San Francisco over Arizona, 19-16