SEATTLE — Aaron Curry couldn’t believe it: a free shot at an NFL quarterback.

“I thought something was up. I mean, who comes free in the NFL?” the Seahawks’ prized fourth overall draft pick said Thursday night.

Ah, the rookie had never played the Raiders.

Curry took advantage of being the only starter on the field Thursday night. He made four tackles, two for losses, hit quarterbacks twice, then sacked one and forced a fumble to set up a field goal. And that was just in the first half of Seattle’s 31-21 victory over Oakland.

Curry’s emergence — and the announcement second-round pick Max Unger will start at right guard when the games get real on Sept. 13 against St. Louis — were the most important Seahawks developments.

Far less important: Seattle and new coach Jim Mora, coming off a 4-12 season, finished 4-0 in the preseason for the first time in its 34-year history.

The Detroit Lions did the same thing last summer — and then became the NFL’s first 0-16 team.

Oakland rallied some after being down 31-7 yet finished the preseason 1-3. Still, coach Tom Cable thought his developing players did well putting Saturday’s embarrassing, 38-point home loss to New Orleans behind them.

“The whole thing is about how we responded to last week, and I think we did a great job of that,” said Cable, who went to high school in the Seattle suburb of Snohomish. “I think in the past we would have just stayed in that mode, ’Whoa is we,’ and we didn’t do that. And that’s a step in the right direction.”

The Seahawks had 12 starters skip the meaningless exhibition in the name of preservation. That included every defender except Curry. The former Wake Forest star needed to learn and progress after signing late and then missing one preseason game with an injury.

Mission accomplished.

“He confirmed some of the things we saw on tape, the explosiveness and the speed, and the play-making ability,” Mora said of the dynamic outside linebacker to whom Seattle gave a whopping $34 million guaranteed last month. “Aaron missed 11 practices, and then missed a week when he got hurt, and yet he has shown an ability to pick things up quickly.

“He can do a lot of things.”

Like this: Late in the first half, he sped untouched around left end and hit quarterback Bruce Gradkowski just as he was about to throw. Nick Reed, a far-less-ballyhooed rookie who probably made the team, grabbed the fumble and returned it 16 yards to the Oakland 14.

“I was just licking my chops, wide-eyed,” Curry said.

The Raiders used each of their first-team units for just one series. Injured middle linebacker Kirk Morrison (left elbow) and All-Pro cornerback Nnamdi Asomugha sat out. Asomugha, with a cast on his left wrist, isn’t expected to miss the opener against San Diego on Sept. 14.

The first play for Oakland’s starting offense was a reminder of the Saints debacle, when the starters got their most extensive time of the preseason. Backed up to his own 8, JaMarcus Russell was sacked by linebacker David Hawthorne. After a 4-yard run by Darren McFadden and an 4-yard dump-off pass to Michael Bush, the starters were done.

So much for redeeming themselves. But, hey, at least they left healthy and with the game scoreless.

Russell, the first overall pick in 2007 who went 26 for 39 passing with one touchdown in the preseason, said he wanted to go back out for more.

“You get so amped up ... and prepare like you’re going to play the whole game, only to get a series,” he said. “But you have to give other guys a chance to go out there and prove themselves, too.”

Veteran Jeff Garcia briefly replaced Russell and was 3 for 6 for 12 yards. Gradkowski was 6 for 10 for 75 yards.

Seattle’s starting offense, still without injured left tackle Walter Jones and center Chris Spencer, also played just one series. Quarterback Matt Hasselbeck, who missed nine games last season with a bad back, never had a chance to get hit. He handed off five times then departed.

Two of those runs were by Edgerrin James, who made his Seattle debut. The NFL’s leading active rusher with 12,121 yards, signed last month as a free agent, ran behind right tackle Ray Willis and fullback Justin Griffith for four yards and seven yards on the game’s first two plays.

Third-string rookie Mike Teel was 11 of 19 for 148 yards and two touchdowns, with backup Seneca Wallace also resting. Teel’s second touchdown of the half was Ben Obomanu’s impressive, reaching catch while toeing the sideline in the end zone for a 38-yard scoring play.