NAPA — Raiders coach Jack Del Rio barks out orders for up-downs whenever there’s a mistake in team drills.

The offense fumbles a snap, that’s five up-downs. Defense jumps offsides, five for that side.

That’s nothing compared to training camps Del Rio experienced as a player in the ’80s and ’90s, seasons that helped mold Del Rio as a coach and give him instant credibility with his players.

“We went 21 straight days in double days, full pads, and we’d tackle in the morning and thud in the afternoon,” Del Rio said. “It’s changed all right, but it’s still demanding. It’s still a physical confrontation. They’re still exerting a lot of energy and you still have a lot of time in meetings and lifting. Training camp is still not something for the group that wouldn’t want to be ready to push and work really hard.”

That Del Rio and much of the Raiders coaching staff have been through those battles means something to the players. It’s worth noting that Del Rio’s predecessor, Dennis Allen, never played a regular-season game in the NFL.

“I think for any player, when you have a guy that played the game, he knows the scrutiny put on you as a player,” said safety Charles Woodson, now in his 18th year. “He knows the bumps and bruises that you take on a day-in and day-out basis. He knows about being in training camp. He knows about what it takes to win. It’s validation for that guy when he played the game.”

On the Raiders’ staff, it starts with Del Rio and his 11 seasons in the NFL. Defensive coordinator Ken Norton Jr. played 18 years and was a three-time Super Bowl champion. Offensive coordinator Bill Musgrave was a reserve quarterback for six years.

There’s a Hall of Fame player in Rod Woodson, the assistant defensive backs coach. Offensive line coach Mike Tice played 14 years in the NFL. Defensive backs coach Marcus Robertson and Rob Moore both played a dozen seasons and running backs coach Bernie Parmalee played nine.

But Del Rio downplays any significance his staff’s playing experience has. This season only seven of the 32 head coaches, 22 percent, played a regular-season game in the NFL. Last year the number was six.

“There are a lot of excellent coaches that never played the game, so I don’t think it has a whole lot to do with whether you can coach or not,” he said.

Rookie wide receiver Amari Cooper agrees. He played collegiately for Nick Saban, who never played a snap of pro ball.

“I believe that guys that didn’t play can be just as good as a coach because they might have learned things from guys who did play, so it’s not really a huge difference,” Cooper said.

That makes sense coming from a rookie, but reaching veteran players can be a bigger challenge and that’s where this coaching staff could have an advantage.

“You hear ex-players talk about things, you know they’ve been there and done that,” defensive end Justin Tuck said. “Especially players that played at that high a level, and also had success coaching too. It makes it easier to listen for us players that think we know it all. Coming from them I think it has a different pull to it.”

Norton, the linebackers coach for the Seahawks the past five years, was fiery as a player and remains fiery as a coach. His philosophy is for his players to learn from any mistakes he may have made.

“We’re not going to ask them to do anything that we haven’t done,” Norton said. “The bumps and bruises and mistakes have already been made before. We’ve made it so they don’t have to make those mistakes. I think they respect that.”

The Raiders signed wide receiver Devon Wylie, a 2012 fourth-round pick of the Kansas City Chiefs. They waived undrafted receiver Austin Willis to make room on the roster. The 5-foot-9, 185-pound Wylie spent time on the 49ers and St. Louis Rams’ practice squads last year. His last NFL action came with the Tennessee Titans in 2013 when he spent two games as a kick and punt returner. The Raiders will look at him as a slot receiver and punt returner.