SERIES HISTORY: The 50th meeting in a series that dates back to 1951. The 49ers lead the all-time series, 29-20. Last season, the Cardinals earned just their fourth-ever sweep of San Francisco and first since 2008. In Week 12, Arizona snapped a six-game losing streak on the road against the 49ers with a 19-13 victory. Overall, Arizona is just 9-16 on the road against San Francisco. Cardinals receiver Larry Fitzgerald enters the game with 14 career touchdown receptions against the 49ers. No player in NFL history has more receiving touchdowns vs. San Francisco. Fitzgerald's 1,854 receiving yards against San Francisco are more than he has against any other opponent.
INJURY UPDATE: San Francisco 49ers linebacker Aaron Lynch was removed from the roster-exemption list and activated, and linebacker NaVorro Bowman was placed on the injured reserve list, the team announced Thursday.
Lynch was suspended for the first four games of the season for violating the league's policy on substance abuse. He is eligible to play in tonight's game against the Arizona Cardinals, although it is unclear whether he will get into the game.
The 49ers need a better pass rush, and Lynch had 12.5 sacks in 30 games (including 16 starts) in his first two NFL seasons.
Bowman is out for the season after suffering a torn Achilles' tendon in Sunday's loss to the Dallas Cowboys.
Leading receiver Jeremy Kerley (ankle) is questionable.
Drew Stanton will start Thursday night's game when the Arizona Cardinals visit the San Francisco 49ers to kick off Week 5 in the NFL.
The Cardinals (1-3) ruled out starting quarterback Carson Palmer, who is dealing with a concussion.
The veteran left Sunday's loss at the Los Angeles Rams with the injury and did not clear the NFL's mandated medical protocol on a short week of preparation.
Stanton threw two interceptions in relief of Palmer at Los Angeles, but went 5-3 as the Cardinals' starter when Palmer was lost for the season in 2014 with a knee injury.
"It's unfortunate we're coming off a short week but that's the way this league is built," Stanton said. "You have to be able to go in, especially somebody in my role."
KEYS TO THE GAME: Whether QB Carson Palmer (concussion protocol) or backup Drew Stanton plays, look for the Cardinals to get the ball in the hands of RB David Johnson as often as they can. With 49ers ILB NaVorro Bowman (Achilles) out for the season, the key to stopping Arizona's rushing attack may fall replacement Nick Bellore or Gerald Hodges. And Johnson is a tough test for 49ers linebacker tryouts.
The Cardinals might be 1-3, but their defense has created turnovers, including seven interceptions. It would be wise for the 49ers' offense to focus on the running game, featuring RB Carlos Hyde, against a team that allowed Buffalo's LeSean McCoy to rush for 110 yards and two scores. Then again, the Cardinals appeared to grow from that performance, limiting Los Angeles' Todd Gurley to 33 yards last week.
MATCHUPS TO WATCH:
--Cardinals QB, probably Drew Stanton, vs. 49ers OLB Aaron Lynch. With Carson Palmer likely out, Stanton must not make the type of mistake that might spell the difference in a competitive game. The pass-rushing Lynch should be full of energy in his season debut after a suspension for violating the league's substance-abuse policy. The 49ers have been good at forcing turnovers this season (plus-2).
--49ers RB Carlos Hyde vs. Cardinals' run defense. The key to stopping the run for Arizona is SS Tony Jefferson. He has been all over the field this season, recording at least nine tackles in each game. He was a big reason the Cardinals limited the Rams' Todd Gurley to 33 yards last week. His goal this week: Keep Hyde out of the end zone, where he landed five times this season.
Cardinals DB Tyrann Mathieu. Keep an eye on the Honey Badger, who is ready to return to his regular role in the slot, playing closer to the box where he can have more of a direct impact on plays. His surgically repaired right knee wouldn't allow it to start the season, as Mathieu played mostly deep safety through the first four weeks. However, he was closer to the line of scrimmage against the Bills and the Rams and thinks he is ready to do it full-time Thursday night against the 49ers. San Francisco will have to account for him at all times. Mathieu can be a game-changer and was in the thick of consideration for Defensive Player of the Year before he was sidelined last season.
Cardinals RB David Johnson leads NFL with 510 scrimmage yards. He is the first player in franchise history to record at least 100 scrimmage yards in each of first four games of a season.
Arizona LBs Chandler Jones and Markus Golden each have a sack in all four games this season, a franchise first. Golden has a sack in the past six games.
49ers RB Carlos Hyde leads the NFC (and is second in the NFL) with five rushing touchdowns.
WR Jeremy Kerley leads San Francisco with 18 catches and 202 yards and is averaging 14.3 yards per punt return.
Arizona was expected to be one of the best teams in the league this year and San Francisco one of the worst. But each is 1-3, with the Cardinals not doing as well as expected, and the 49ers are playing more competitively than predicted. The Cardinals do have better players on both sides of the ball, even with a backup at quarterback.
OUR PICK: Cardinals, 28-21.
--By Frank Cooney