Quarterback Carson Palmer delivers a pass in the 22-19 loss to the Chargers on Saturday.

The perfectionist in Carson Palmer wasn't happy about the mistakes made by the first-team offense in Saturday's 22-19 preseason loss to the Chargers. After a flawless performance in last week's opener, the veteran quarterback completed only 3-of-7 passes and was sacked twice, mainly due to the group's self-inflicted errors.

But spliced in around those slip-ups were some impressive signs of what the unit could become in the regular season.

Palmer's three completions went f

or an average of 29.3 yards, including a 57-yard bomb to rookie wideout J.J. Nelson. The long gain pushed the Cardinals into San Diego territory, and Palmer hit John Brown for a 17-yard touchdown to cap a five-play, 80-yard drive. Even with a completion percentage of only 42.8, Palmer finished the game with a shiny quarterback rating of 129.5.

Palmer thought he overthrew Nelson, but the fastest man at this year's NFL Scouting combine actually had to slow down and wait for the ball as it dropped into his hands. Brown left defensive backs in his wake, and running back Andre Ellington would have added an easy catch if he and Palmer didn't get their wires crossed on a pass play.

"It just leaves you wanting more," Palmer said. "It's kind of a little bit of a tease."

Palmer was slated to play the entire first quarter, but coach Bruce Arians pulled him a few minutes early after three series. The Cardinals are balancing a tight-rope between getting Palmer game action and keeping him out of harm's way, and after a few hits Arians had seen enough.

After remaining upright in the opener, Palmer said the sacks were actually something he appreciated.

"It's just good to get those out of the way and get your body acclimated," Palmer said.

MIXED RESULTS FOR OFFENSIVE LINE

The new-look offensiv

e line made its debut against San Diego, with Ted Larsen at left guard and Bradley Sowell at right tackle. The performance was a mixed bag, as the group opened up some nice running lanes but also had a handful of mistakes.

Sowell was beaten for a sack, as was left tackle Jared Veldheer. Larsen received a 15-yard personal foul penalty deep in Chargers' territory.

"Bradley got beat on a spin move early and Larsen got a real dumb penalty that cost us a drive, so not real good," said Arians when asked of the group's performance.

All told, the Cardinals gave up six sacks in the first half, but averaged five yards per carry.

"There's going to be some good and some bad on the film, but once we get it all together I think we'll be good," Sowell said.

First-round draft pick D.J. Humphries worked with the second team at right tackle but gave up a sack.

"Bad technique and bad effort," Arians said. "He got outfought. Simple as that."

CHRIS JOHNSON SITS WITH HAMSTRING INJURY

Running back Chris Johnson was expected to make his Cardinals debut but injured his hamstring in the last play of practice on Thursday. He is expected to miss one or two weeks, Arians said. Cornerback Jerraud Powers (oblique) and tight end Jermaine Gresham (back) also sat out. Neither has played in the preseason.

Wide receiver Brittan Golden headed to the locker room about midway through the fourth quarter after taking a couple of big hits.

EXTRA POINT WOES

Both teams failed on one of their new, longer-distance extra-point tries, although only San Diego's was a legitimate miss. The Chargers were set to cut their deficit to 9-6 after a second-quarter touchdown, but Nick Novak knocked his kick off the upright.

The Cardinals' point after failed after their first touchdown, but it came on a botched snap.