After an uneven performance against Dallas in its preseason opener, I’m not going to say that Oakland has turned the corner on a seven-year run of bad football, but things are starting to look a little brighter for the silver and black.

Changes are happening in Oakland, but it’s not all focused on the glamour positions.

Certainly, Jason Campbell has proven to be an upgrade over JaMarcus Russell, but after just one preseason game, the defense has stolen the show—especially if the new schemes and personnel continue to work.

For starters, the defense allowed just 66 yards rushing, which looks to be a huge improvement from years past, when Oakland ranked near the bottom of the league in that department.

Still, it’s only preseason and not much can be gained from that.

To be convincing to the doubters, the defense needs to show that it can play at this level week in and week out. A new defensive front, along with the concept of allowing Nnamdi Asomugha to freelance in the secondary, could make this defense as fearsome as something found only in depths of the Black Hole.

Moving Richard Seymour to the inside, with a slimmed down Tommy Kelly at nose-tackle, has allowed single blocking for the Raiders’ youthful ends. With the type of speed Oakland has here, it’s essentially a free pass to the quarterback.

Both Lamarr Houston and Matt Shaughnessy received high praise for their efforts against the Cowboys last Thursday night—as each racked up a pair of sacks on the bewildered Cowboys line.

In a new twist, two-time Pro Bowl cornerback Nnamdi Asomugha will now get to roam free in the secondary and cover the opponents’ best receiver with regularity. We’ve heard of “Revis Island,” now we’ll see if the Raiders shut-down corner is up to par with his counterpart in New York.

Asomugha says that the fans will finally see what NFL coaches and personnel men have known for a while.

“There are so many times when I feel like I’m having the game of my life and no one knows it,” Asomugha said. “That’s rough. No one sees it. The offenses see it, the people that watch film see it but the fans don’t see it.”

The national media hasn’t lost sight of the team’s defensive upgrades. ESPN.com senior writer John Clayton said linebacker Rolando McClain and Houston have both performed as expected throughout the first week of preseason. And SI’s Peter King had this to say about the Raiders in his latest edition of Monday Morning Quarterback:

“The Raiders looked better than we all thought. Smart to keep Tom Cable and give the team continuity, and smart to play an attacking style of defense from the first preseason series. I also hear nothing but good things about the job Hue Jackson’s doing as offensive coordinator.”

OK, I get the fact that Oakland’s NFL-worst 29-83 record over the last seven years is an embarrassment. And it’s not just the media who remains skeptical about the new and improved Raiders, it’s everyone. It’s time to put up or shut up.

Success for the Raiders hinges on many things. It’s not hard to envision things going south— the offense may have a huge melt-down without a clear No. 1 running back.

Michael Bush should be the guy, but Darren McFadden is the top pick from two seasons ago. If Campbell doesn’t find early success in the passing game, panic could set in—Cable could be fired and Oakland could easily wind up going 6-10.

On the other hand, if this defense continues to develop and Campbell is not forced to shoulder the burden of winning games with his arm, Oakland may have a formula for success, à la the 2000 Baltimore Ravens.

Getting back to Campbell, he went 7 of 13 for 49 yards and had a passer rating of 62.7 in his debut. Reaction: Meh…That was basically what he did as a Redskin.

In his postgame remarks, Campbell was optimistic about building a better rapport with this young but talented group of pass catchers, saying the deep ball was there.

“We missed it by a half-step. That shows you that there is a reason to be confident about things,” he said.

In camp, the connection with Zach Miller is undeniable, but will the rest of the Raiders receivers catch on?

Specifically, all eyes have been on No. 1 selection Darrius Heyward-Bey and to a lesser extent, standout Louis Murphy.

Last week in Dallas, there wasn’t much to see from either receiver. Campbell threw in Heyward-Bey’s direction in the first series but came up empty. Saturday at Chicago, expect the Raiders to find Heyward-Bey early and often.

More importantly, it’s now time for Bush to solidify his position as the team’s starting tail back. In 2009, Bush led the Raiders in rushing with 589 yards and three touchdowns. Some will argue that he did it without getting the ball nearly enough. But it’s hard to run the ball when you’re behind on the scoreboard.

Still, 14 is a key stat to remember with this power runner. That’s the number of times Bush carried the ball in his two 100-yard performances in ‘09. Oakland will need more of the same this season.

Cable and Hue Jackson may be tempted to get McFadden heavily involved in the power running game—just to see if he can provide a spark—but that would be a mistake, given McFadden’s injury history.

Yes, he has homerun capability, but the fourth-overall pick from 2008 isn’t nearly as durable a runner. Bush is the real work horse in this offense and has to start proving it soon.

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