NAPA – The Raiders' first-team offense has yet to score a touchdown in the preseason, but that isn't keeping quarterback Carson Palmer awake nights.

"Obviously we haven't done what we expected to do, but it's not a concern," Palmer said Tuesday. "We just need to clean some things up. We've made a handful of mistakes and hurt ourselves, but it's not concerning."

In the first half of the Raiders' 31-27 loss to Arizona on Friday night, Palmer completed 13 of 24 passes for 107 yards and threw his second preseason interception. He led a pair of long drives that stalled near the goal line as the Raiders settled for Sebastian Janikowski field goals.

"I think that's the main thing that's encouraging to know is that we've made a bunch of mistakes and we've still moved the ball, but we've been nowhere near where we can be when we're all clicking and on the same page," Palmer said. "It's just a matter of time. We just need to keep working."

Palmer said at this point in camp he's trying to fine-tune things such as reads and footwork. Building a rapport with receivers, he said, is "always a work in progress," and has been made difficult by recent injuries in the receiving corps.

Darrius Heyward-Bey returned Tuesday after sitting out practice Sunday with a sore shoulder, but Jacoby Ford (foot) and Denarius Moore (hamstring) are still out, with Moore's return closer than Ford's but still up in the air.

The result has been more first-team reps for rookies Rod Streater and Juron Criner. Coach Dennis Allen said Streater, who has caught 13 passes for 109 yards in two preseason games, is in line to start Saturday against the Detroit Lions in place of Ford.

"They're in the right spot at the right time – they're not lining up in different formations with wrong splits or breaking the huddle and running the wrong way, which is a lot of times something that happens with young guys," Palmer said of the rookies. "So I have a ton of trust in them, and we'll just continue to work on it as the year goes on."

Carter workout – The Raiders brought in free-agent defensive end Andre Carter for a workout Tuesday. Carter had 10 sacks in 14 games for New England last season before having his season cut short by a left quadriceps tear.

"I've got to stay low-key," Carter said while leaving the practice field. "If it works out, God willing …"

The Raiders may want to add to their pass rush after cutting Kamerion Wimbley (seven sacks in 2011) in March. Carter, formerly of the Washington Redskins and 49ers, has 76 career sacks in 11 seasons.

"We're going to shake all the bushes and see what falls out, and if we feel like we've got something that can help us, we're going to do it," Allen said.

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by Matt Kawahara

Order Reprint