As the Oakland Raiders’ defense prepare for their toughest test of the preseason against the Detroit Lions, defensive coordinator Jason Tarver wants to see the defense continue to show progression. As a first year defense coordinator in the NFL, Tarver is teaching his defense to a new team, but likes what he has seen with team work and process.

“It’s all about process, it really is,” Tarver said. “It’s about teaching progression and processing. Putting everything together in categories so we can progress where we want to go. It’s great that they can see that because now they are putting those things together, going, ‘oh this looks like this. I see myself in this making plays.’ But now we’ve got to do it and we have to do it with 11 guys together.”

Tarver broke into the NFL with the San Francisco 49ers and spent 10 years with the team, most coming as a linebackers coach. Last season he jumped to Stanford to be the co-defensive coordinator and the Cardinal led the Pac 12 in six defense categories. After all he has a master’s degree in biochemistry and molecular biology helping him match wits against the offense.

The first year Raiders’ defensive coordinator wants to utilize multiple defensive looks and schemes. He will be tasked with improving a defense that last season ranked 27th against both the run and the pass. He will use both man and zone coverages. One of the most important aspects Tarver wants to bring to the Raiders is pressure by dialing up blitzes.

“There’s good pressure at times,” Tarver said. “More encouraged is the guys working together and the mindset. It’s about mindset, it’s about I know where I’m going and you’ve got to deal with me.”

There has been much chatter from players like Michael Huff and Richard Seymour that this Raiders defense under Tarver has a chance to be top five. The players love the system because it allows them to be aggressive and make plays. As far as being a top five defense when 2012 is done, Tarver defines good defense in his terms.

“How do you rank a top-five defense” Tarver said. “There’s a lot of ways, but the biggest one is getting the heck off the field and getting the ball to Carson and the guys. That’s the biggest one, that’s what we want to do. The other stats with that, that’s a result of controlling how we get off the field. Third down percentage, red zone touchdown percentage, those are a couple that are good markers.

With the third NFL preseason game widely regarded as the closest to a regular season game as far as starters playing more time and game planning for a specific opponent, Tarver sees the Detroit Lions as a significant challenge. Matthew Stafford, Calvin Johnson and company will give the Raiders defense their best test of the offseason.

“It’s a good order for us,” Tarver said. “You got Dallas that can throw it, and wants to run [the ball] downhill at you. You have Arizona who shifts a little bit and still runs downhill at you, and of course as a good wide receiver. And then you have Detroit that runs it more than most people think they do, but it is a little bit more spread out and they try to get match-ups for their good players. Of course we know the guy with the nickname who is on the cover of ESPN The Magazine this week. But they have other players, and that quarterback he gets it out. It’s kind of a nice progression for us. Facing those three, two styles, and a little slightly different style, with slightly different personnel groups. So we can learn how to use our rules for all our different defenses.”

NAPA — Richard Seymour has not practiced since Friday night’s exhibition at Arizona, sitting out the last three practices, and while the Raiders defensive tackle has had what’s been described as a troublesome knee early in camp, Seymour sitting out is more a courtesy extended a veteran than anything else.

“It’s not an injury,” said Raiders rookie coach Dennis Allen. “He’s an older veteran guy and his knees get a little sore, so we try to rest him to make sure we get him ready to play.

“When a guy gets more age on him, you have to be careful as far as how much you use him. The deal is we have to get him enough work to get him ready to play, but yet have him ready to play so we can have him for a full 16 games this year.”

Seymour, who turns 33 on Oct. 6, is entering his 12th NFL season.

“I think anytime you go into camp you kind of know at some point in time some of these veteran players are going to need some time off,” Allen said. “He pushed real hard early in camp and then as we kind have gotten into camp, we’ve taken more time off with him.”

Still, Allen said Seymour is expected to play Saturday against Detro

NAPA — Raiders center Stefen Wisniewski’s strained calf is not only keeping him from live reps in practice but will most likely keep him out of Oakland’s all-important third exhibition game, Saturday against Detroit.

“I wouldn’t expect him to play this week, no,” Raiders coach Dennis Allen said following practice Wednesday.

Wisniewski, the Raiders’ top draft pick out of Penn State in 2011, is learning a new position after excelling at left guard last year. He was injured, though, in the Raiders’ preseason opener against Dallas on Aug. 13.

So is Wisniewski simply too hurt to play this week, or is it too close to the regular season to risk further injury?

“It’s a little bit of both,” Allen said. “If we were in the regular season could he push through and play? Probably. Maybe. I don’t know.

“We’re not going to take that chance right now in a preseason game.”

Alex Parsons has been taking the first-team snaps at center and no matter who gets the call on Sept. 10, he will be the Raiders’ sixth different starting center in as many years.

NAPA — Stefen Wisniewski missed all of the Raiders’ offseason training programs, having undergone shoulder surgery.

And since the Raiders’ first offensive series against Dallas in each team’s exhibition opener, Wisniewski has been sidelined by a strained calf.

Not exactly what you need from a guy making the transition to center from left guard, right?

“He needs to get the reps,” coach Dennis Allen said Tuesday of Wisniewski. “It’s football and you don’t just show up and play, so every day he’s not out here he’s a little bit farther behind.

“But he’s been keeping up mentally as far as taking the mental reps and in the meetings, but it’s hard to replace those physical reps you get here and in games.”

In his place at center, practice squad refugee Alex Parsons has excelled and all-but-solidified his place on the Raiders’ 53-man roster.

“Offseason was awesome,” Parsons said. “The fact that you get he reps and you’re going against the two tough guys, obviously, Tommy Kelly and (Richard) Seymour. The fact that you get the reps, you can have your system down.”

Parsons said he dropped 18 pounds from the end of last season, which is also helping his play. And appearance.

“I look better in white,” Parsons joked. “I don’t have that gut. There’s a huge difference conditioning-wise as well.”

Getting all of Wisniewski’s reps of late does not hurt, either.

“He’s done well,” Allen said. “He’s done well. As a matter of fact, he was competing the whole time and we were impressed with what we’ve seen out of him. Again, we’ve got a next-man-up philosophy. If Wiz is ready to go, great. If not, then it’s next-man-up and Alex will go in there and play and we expect to see results from him, and he’s given us every indication that we’ll see that.”

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Allen said with Jacoby Ford and his sore left foot — he was still walking around in a boot Tuesday after hurting it Friday — unlikely to play and Denarius Moore still nursing a sore hamstring, undrafted rookie Rod Streater would start at one of the receiver spots against Detroit on Saturday.

“Again, next-man-up philosophy,” Allen said. “He’s the next man up on the list. We put him up and go out and do your job.”

Streater has 13 catches for 109 yards in two preseason games.

“He’s been forced into the starting role and because of injuries, it doesn’t seem like he’s earned it,” said quarterback Carson Palmer. “But he can play with the best of them.”

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Free safety Michael Huff returned to the Raiders after being excused last weekend to attend the birth of his daughter, Madeline Rae.

“She was 6 (pounds), 2 (ounces),” Huff said. “She was born (at) 4:24. That’s a great number, the 24. I made sure I pulled her right out at 24. I was looking at the clock.”

For those of you needing a program, yes, Huff wears No. 24.

NAPA, Calif. — Stefen Wisniewski has a tough enough adjustment to make in his second year in the NFL after having changed positions and blocking systems with the Oakland Raiders.

Injuries that are keeping him off the practice field are only making that job more difficult.

After missing all off-season workouts while recovering from shoulder surgery, Wisniewski has now been sidelined more than a week with an injured calf sustained in the exhibition opener.

The lack of time on the practice field for Wisniewski is becoming a growing concern for the Raiders, who are counting on Wisniewski to anchor the line at center this season as the team adapts to the zone blocking system.

“He needs to get the reps,” coach Dennis Allen said Tuesday. “It’s football and you don’t just show up and play so every day he’s not out here he’s a little bit further behind. But he’s been keeping up mentally as far as taking the mental reps and in the meetings but it’s hard to replace those physical reps you get here and in games.”

Wisniewski suffered the shoulder injury in his rookie season and played through a labrum tear for most of the year. He still was impressive for the most part as a key part of Oakland’s line at left guard, but did struggle at times late in the season.

He had surgery after the season and spent the entire off-season program rehabbing, attending meetings and watching his teammates learn a new system as Oakland moved from a power blocking to a zone blocking scheme that puts more emphasis on quickness than strength for linemen.

“You got to be able to move,” Wisniewski said. “If you look at our O-line, that’s one thing we all can do across the board. We can move, we can run, we’re athletic. So I think it’s going to work for us, especially with the speed we’ve got at running back.”

The Raiders were hoping to give Wisniewski a lot of work in training camp to make up for lost time as he moved to center to replace the departed Samson Satele.

But that ended when he left the exhibition opener against Dallas on Aug. 13 following the first drive with the injured calf. He hasn’t practiced since and with less than three weeks until the season opener against San Diego on Sept. 10, time is of the essence to get Wisniewski ready.

“We talk after every series, every play,” backup center Alex Parsons said. “When we’re out here on the field he’ll come up to me and ask me what happened and what I saw and what he saw and we’ll discuss what happened.”

Parsons has gotten plenty of time to work with the first-team line at center. Parsons originally signed with the Raiders as an undrafted free agent out of Southern California in 2010. He was part of the final cuts after each of his first two training camps, spending two years on the practice squad.

He hopes this is the year he finally sticks.

“It’s tough to see your team out there and you practice with them,” Parsons said. “Last year we didn’t travel to road games. It’s one of those things where you look at your team on TV and you wish you were out there. You just have to make the best of your experience now.”

Parsons came back again this season to Oakland hoping to make the squad on his third try. He lost about 20 pounds, which has made him quicker for the new system.

Now he’s getting a chance to show how that helps him on the field and has impressed his teammates so far.

“We didn’t skip a beat with protection calls, we didn’t skip a beat in the run game,” quarterback Carson Palmer said. “Everything was just kind of flowing and easy and there weren’t any mental mistakes as far as that’s concerned. When you’re in the huddle with a guy and you notice that he’s a rookie, that he’s a guy that hasn’t been in the huddle a bunch, that’s concerning, and it’s not that way at all with Alex.He’s been on top of everything.”

Here are five things to keep an eye on Saturday night as the Lions play the Raiders in their third preseason game:

• Leshoure thing: Sixteen months after they drafted him, Mikel Leshoure is finally expected to make his Lions debut. Leshoure tore his Achilles tendon last year and missed most of camp this year with a strained hamstring. He’ll play plenty Saturday as the Lions try to get him ready for the season.

• More: Hope runs deeps for Leshoure’s Lions debut

• Half and half: Matthew Stafford, Calvin Johnson and other starters will play about a half Saturday. Pay close attention, cause this will be your last extended look at them until games count.

• More: QB Kellen Moore locks up Lions’ third-string spot

• Under cover: The Lions struggled mightily on special teams last week against the Ravens. Keep an eye on their coverage and return units Saturday. They made a few minor changes, and some of the faces you’ll see are fighting for jobs.

• Rush hour: Oakland ranked seventh in the NFL in rushing last year, so Darren McFadden and Co. should provide a stern test for a Lions defense that struggled stopping the run at times (5.0 ypc allowed). Remember, Stephen Jackson awaits in Week 1.

• First dance: The Lions’ first-team offense doesn’t have a first-quarter point this preseason. It’s not a huge concern considering how little planning goes into exhibition games. Still, it’d be nice to see Stafford find his rhythm early.