ST. LOUIS -- It was a new season with the same old problem for the Arizona Cardinals: a quarterback under siege.
Carson Palmer was solid in his debut for the Cardinals on Sunday, but he was sacked four times and pressured often in a 27-24 loss to the St. Louis Rams.
The biggest culprit was left tackle Levi Brown, who surrendered three sacks to Rams defensive end Robert Quinn, including one in the fourth quarter that led to a fumble that set up the Rams' tying field goal.
"Other than the three sacks I had a pretty good day," Brown said sarcastically. "You can't do that at the left tackle position and expect to win games."
Rams tight end Jared Cook caught two touchdowns and had a key reception in the drive that led to Greg Zuerlein's tiebreaking field goal with 40 seconds to go, completing a comeback from an 11-point fourth-quarter deficit. Sam Bradford was 27 for 38 for 299 yards, two touchdowns and one interception.
After catching just four touchdown passes last season, Larry Fitzgerald caught two Sunday from Palmer, acquired from Oakland for a sixth-round draft pick. Palmer was 26 for 40 for 327 yards and an interception. Fitzgerald had eight catches for 80 yards.
Arizona's defense was almost enough, even scoring a touchdown.
Bradford and Cook connected down the middle in the first quarter and Cook seemed on his way to a 55-yard score. Rookie Tyrann Mathieu caught up to him and punched away the ball at the 8, the fumble recovered by Arizona in the end zone for a touchback.
Mathieu arrived with a big-play reputation as a third-round pick out of LSU, where in two seasons he forced 11 fumbles and recovered eight, with two touchdowns. He said he never gave up on the play because he figured he could catch a tight end.
"Luckily, he never even looked at me, so I was able to just come up from behind him and punch the ball out," Mathieu said.
Bradford said he encouraged Cook to forget about it.
"I told him when we came back to the sideline, I said, 'Hey bro, be ready. It's coming right back to you,'" Bradford said. "It would have been easy for him to get down out there. He showed a ton of maturity and confidence."
The Arizona defense scored in the third quarter when Bradford's pass from his end zone was tipped by Matt Shaughnessy and caught by defensive tackle Dan Williams, who essentially fell into the end zone for his first career touchdown.
Fitzgerald scored on a 4-yard first-quarter fade from Palmer, and his 24-yard scoring catch with 1:47 to play in the third quarter put the Cardinals up 24-13.
After that, it was all St. Louis. The Rams got within three on Bradford's 1-yard pass to Cook, and Bradford's 2-point conversion run with 13:01 to play. After Quinn's forced fumble on Arizona's next series, Zuerlein tied it with a 38-yard kick.
The Cardinals' offense stalled, managing just three first downs in the fourth quarter. The Rams drove from their 20 to the Arizona 30 in one minute to set up Zuerlein's fourth and final field goal, a 48-yarder, with 45 seconds left.
Cook had seven catches for 141 yards and the first multi-touchdown game of his career in his first game with the Rams after signing as a free agent. He scored on a 13-yard reception that tied it at 10 with 26 seconds to go in the first half, stretching the ball across the pylon while getting shoved out of bounds by Yeremiah Bell.
Rams coach Jeff Fisher characterized Cook's effort as "near perfection, with the exception."
Arizona surrendered an NFL-worst 58 sacks in 2012. The Cardinals addressed the concern by drafting guard Jonathan Cooper in the first round, but he is lost for the season with a broken leg suffered in the third preseason game.
Beyond Brown, the rest of the line includes a pair who didn't play a down last season. Daryn Colledge moved back to left guard after Cooper's injury, and right guard Paul Fanaika was out of football last season. Brown missed 2012 with a torn triceps.
Arians, anticipating the question, said no changes are planned on the offensive line.
"Obviously, they (the Rams) have a great pass rush and no, I'm not concerned about the offensive line," he said.
Asked specifically if he would go to someone other than Brown at left tackle, he asked, "To who? You got one? He's our guy."