Site: The Raiders Napa Valley Training Complex. Located 10 minutes from downtown Napa and five minutes from rows and rows of vineyards.

What I Saw: Saturday morning practice, Sunday night practice (the team’s first in full pads) and Monday morning practice.

Three things you need to know about Oakland

1. They’re simplifying on defense. After spending three seasons under coordinator Jason Tarver and his smart but voluminous scheme (Tarver and head coach Dennis Allen worked together on it), they’re moving to Jack Del Rio’s more traditional zone-based defense. “I feel more comfortable in the scheme we’re playing now,” third-year cornerback D.J. Hayden told me after Saturday’s practice. “Last year’s scheme was good. But when (the scheme’s) simpler, you don’t have to think as much and you can just play faster.”

Hayden’s running mate, ascending second-year cornerback T.J. Carrie, had a slightly different take, saying both staffs put the players in great positions to succeed and that there are so many variations to every coverage that it’s essentially all minutia anyway. “And in the end, they’re all just some form of man, zone or fire zone,” he said, explaining how coverages are not play calls per se, but rather, just concepts.

In the holistic sense, Carrie is exactly right. But the decreases in what he calls “fire zones” (i.e. rotations and disguises) makes for an increase in the more straight-forward coverage concepts. With this, the talented young Raiders defense should at least play faster in 2015.

2. Don’t believe Khalil Mack’s rookie sack total (4).It’s as misleading as any statistic I’ve ever seen. Week in and week out, Mack jumped off the film. He was as good as almost any defensive end in the league. It just so happened it didn’t translate to sacks. I asked him about that, acknowledging that he probably gets asked about it all the time. “Yeah, I’m asking myself about it,” he said. He didn’t seem too bothered by it, though.

“Justin Tuck told me, sometimes people get lucky,” Mack said. “Across the league, you see some guys just show up and the scheme, and maybe just (the nature of) a particular play, allows them to be in the right position.” He said this with no hint of resentment or dismay. He did, however, seem pleasantly surprised when I informed him that, according to Football Outsiders, he ranked second in the league in drawn holding penalties, with eight. But mostly he talked about what he must do to improve his game. He cited “fundamentals” and applying them “throughout the whole game, being consistent” as his area in most need of work. “I can’t just rely on athleticism,” he added. To better understand fundamentals and various moves, he spent significant time this past offseason studying other pass rushers around the league, most notably, Dolphins veteran Cameron Wake, whom he lauded unequivocally.

In practice, Mack, lined up as the weak side defensive end on the vast majority of snap. The “Leo,” as it’s called in this scheme. He’ll draw a lot of one-on-one blocking that way. Expect his sack numbers to soar.

3. The receiving corps is better – thank goodness. In recent years, the Raiders haven’t had anyone who can beat man coverage. We’re seeing already that now they have two guys who can. In practice, corners struggled to stay with first-round rookie Amari Cooper, and a few of them got frustrated trying to defend Michael Crabtree. “He has a great sense for making you as a corner do something you don’t want to do,” Carrie said, lauding about veteran’s body control and mechanics.

What will determine success or failure of Raiders: The defense’s adaptation to the new scheme. Just because it’s simpler doesn’t mean it doesn’t still have nuances that must be perfected. The linebackers, in particular, have a ways to go here. (Or maybe linebackers coach Sal Sunseri is just nitpicky. Watching Sunseri instruct his player, by the way, was the highlight of camp. He has a passion for details and a way with words.) Offensively, the Raiders must stay healthy at receiver and become more consistent up front in run-blocking.

Player I saw and really liked: Tight end Mychal Rivera. He aligned in a variety of spots across different formations, most notably in the slot, where he covers a lot of ground as a long-striding interior route runner. Rivera showed excellent body control and consistently snatched balls away from his body.

Five dot-dot-dot observations about the Raiders: Everything quarterback Derek Carr does is compact. His footwork, his windup, his release. Raiders fans should be excited about their QB…..Speaking of Raiders fans, they’re a rowdy bunch. I mean this in a nice way. They organize chants, shout at players with good-natured relentlessness and gladly brave the sun even though most wear all black. At one point, in the restaurant bar of the hotel where the Raiders are staying, fans spotted Mark Davis sitting in a back corner booth. Chants of “Stay in Oakland (clap-clap-clap)” erupted, a not uncommon occurrence this weekend in Napa. A nice hotel restaurant bar is about as inappropriate a forum as aggressive chanting can find, but Davis seemed to love it…..The Raiders’ O-line is massive. And oddly shaped. In the right shade of brown pants, Gabe Jackson’s thighs could blend in with the trunks of the nearby redwood trees. Austin Howard looks like he could literally eat a linebacker. And Donald Penn has the body of a sumo wrestler but with the ankles of a long-distance runner. One would think such disproportion would be cause for injury, but Penn hasn’t missed a game in the past seven years. He’s coming off his best season, too…..Free agent pickup Nate Allen will be an important piece to this defense as the box safety. He’ll rotate down in a lot of the coverages, with Charles Woodson playing centerfield....Raiders defensive players probably hear echoes of Ken Norton’s voice as they drift off to sleep each night. The first-year defensive coordinator is a yeller. Not in an accosting way (unless needed), just in a “guy who’s always saying something but because he’s on 53-yard wide field talking to dozens of men at once” sort of way.

The one player on the roster I’d forgotten about: Malcolm Smith, Super Bowl 48 MVP (yes, I’m calling it Super Bowl 48; it’s time to take a stand against the archaic and complicated Roman Numeral system, which vanished hundreds of years ago for a reason). Smith will likely be part of the team’s nickel package and may start opposite Sio Moore at outside ‘backer in the base 4-3. He moves well, plus he played in a similar zone scheme in Seattle.

The one thing I’ll remember about Napa: The county library. Needing to print off 70 pages of a particular team’s film study notes Saturday night so that I could write that team’s preview Sunday morning, I raced to Kinkos, only to learn that they wanted well over $50 for the job. So, thinking I could take advantage of California’s taxpayer dollars, I raced across town to the public library, hoping they’d print them for a smaller fee. They did: $7. And they weren’t going to charge me because I’d arrived just three minutes before closing and the register was already locked. I learned about the register only after I’d already laid out seven one dollar bills on the counter. It would have been an unspeakable display of parsimony to retrieve them at that point, for by then several library staffers had stuck around a few minutes after closing time to help arrange my printing. Grateful, I submitted the $7 as a donation. It occurs to me now that the library must keep the donations in a compartment that’s separate from the register. Anyway, I’ll be writing it off in April.

Gut feeling about this team as I left town: It will be a much better team than it was a year ago. Unfortunately, the AFC West is ultra-competitive, so “much better” might only equal seven or eight wins. But the talent is young and fairly plentiful on both sides of the ball, and the new coaching staff is committed to aiding it with a simpler system.