Out of the postseason race, the San Francisco 49ers and Arizona Cardinals are preparing to start backups because of injuries for their season-ending matchup Sunday in Glendale, Ariz.

San Francisco coach Kyle Shanahan announced Wednesday that Joshua Dobbs will start at quarterback in place of Brock Purdy, who suffered a right elbow contusion with nerve inflammation in Monday's 40-34 loss to the visiting Detroit Lions.

Dobbs, who played eight games for the Cardinals (7-9) last season while Kyler Murray nursed a knee injury, finished Monday's game for San Francisco (6-10).

He played five snaps, completing three of four pass attempts for 35 yards and rushing for a 7-yard touchdown.

Brandon Allen started for Purdy earlier in the season in a 38-10 loss to the Green Bay Packers when the latter was out with a shoulder injury.

"(Dobbs has) been great, him and Brandon," Shanahan said. "They've been two good guys to have there. They both have given really good looks in the scout team.

"They split reps, and they're always ready. They both prepare like they're going to be the starter every week. They've been great."

Tight end George Kittle (ankle, hamstring), wide receiver Deebo Samuel (ribs, wrist) and defensive end Nick Bosa (knee) were noted non-participants in practice through Wednesday.

Arizona placed running back James Conner (knee) on injured reserve this week and signed Michael Carter off the practice squad. Rookie running back Trey Benson (ankle) was also placed on injured reserve, with offensive lineman Nick Leverett signed from the practice squad to fill the roster vacancy.

Carter played the last two games because of the injuries to Conner and Benson and totaled 88 yards on 18 carries and seven receptions for 41 yards.

DeeJay Dallas, the only other running back on the 53-man roster, is likely to get carries. Arizona also has Tony Jones Jr. and Hassan Hall on its practice squad.

"They all have their roles, but (Carter's) going to get a bunch of carries, I'm sure," Arizona coach Jonathan Gannon said.

The teams last met in Santa Clara, Calif., on Oct. 6, when the Cardinals improved to 2-3 with a 24-23 win.

After losing the next week at Green Bay, Arizona won four consecutive games to improve to 6-4 and stand atop the NFC West going into its bye week.

However, the Cardinals have lost five of their last six, including two against division rival Seattle Seahawks, to fall out of playoff contention.

Murray is coming off a 33-completion, 321-yard performance against the host Los Angeles Rams but had two interceptions in the 13-9 loss.

Arizona's lone touchdown was a 1-yard completion from Murray to Trey McBride, who caught his first score this season. He finished with 12 catches for 123 yards.

"I think for me, and any player in general, going into the last game and the offseason, I think it's big to feel good about your last performance," Murray said. "Me, personally, I would like to go into the offseason playing well and have that on my mind."

Shanahan mentioned that although 11 San Francisco players missed practices this week and receiver Ricky Pearsall (illness, chest) and safety Ji'Ayir Brown (ankle) were limited, the last game is not viewed as a way to get reps for younger players.

"Rosters aren't built like that," Shanahan said. "You get to sit five to seven guys. You can sit seven if you bring up two practice squad guys. You don't just sit there and tell every guy who is a veteran he's going to be the backup and play special teams.

"We don't have rosters like that really anywhere. You've got to balance it out to make sure you've got 48 guys who can play."

--Field Level Media