NAPA -- Rookie defensive end Shelby Harris provided one of the bright spots for the Raiders in their exhibition-opening loss to the Minnesota Vikings when he recorded a sack on a play that resulted in a fumble.
Yet, that's not enough collateral for Harris to be immune from a scolding. On Sunday, he was the target of a tongue lashing by coach Dennis Allen for a perceived lack of effort on a particular play.
"Just a reminder about the way we want to practice," Allen said afterward.
Allen's brief outburst was directed at Harris, yet he no doubt raised his voice so that everyone got the message that there's a standard expected of everyone at all times.
"It means don't get comfortable," Harris said afterward. "We came out here to work. That's what he wants us to do, and that's what is expected of us, to come out here and work. I respect him for that. He's willing to get on anyone."
The Raiders failed to meet Allen's standards in Friday's 10-6 loss to the Vikings, with 13 penalties, several dropped passes and inconsistent defensive play.
"They are things that, through my experience, I've seen them happen in the first preseason game," Allen said. "You don't like it, it's not acceptable, but that's why we play preseason games, so that we get a chance to work on these things."
The Raiders conclude the Napa portion of their training camp Monday morning. They then fly to Oxnard, where they will take part in joint practices with the Dallas Cowboys on Tuesday and Wednesday.
On Friday, the Raiders host the Detroit Lions at the Coliseum. In other words, there's limited time for the players to get things worked out before their next dress rehearsal for the regular season.
Allen put his players through a fast-paced practice that featured extensive work in red-zone offense and defense, the two-minute drill and field-goal operation.
"It was good to get back out here after playing a game, get a chance to make some corrections, get out and get some more work in," Allen said. "We got better as a football team."
Harris, a seventh-round draft pick in May, believes he's getting better every day. In fact, he said, he has seen enough to know that he belongs in the NFL.
"I can definitely play at this level," Harris said. "There's no doubt about it in my head. I can go out there and be an impact player wherever I'm needed.
"I have the confidence to play in this league, and I have the skill to play in this league. Now it's just to show everyone else that I have the skill to be able to play every day."
"I still don't have anything to where I can give you an accurate timeline," Allen said of Hayden's return to full-team practice. "It was encouraging that he was out here on the field and able to do some things on the field. Hopefully the process can begin to speed up. A lot of that is going to depend upon how he responds after a day's work."
Hayden was Oakland's first-round pick in 2013. He missed the final eight games last season after he suffered a groin injury.
Linebacker Kaluka Maiava practiced Sunday for the first time since he injured a hamstring early in camp.
Follow Steve Corkran on Twitter at twitter.com/CorkOnTheNFL.
Detroit (1-0) at Raiders (0-1), 7 p.m., KTVU