Oakland Raiders players are scattered across the country enjoying a six-week summer vacation between the end of minicamp in June and July 26, when they report to training camp.

But that doesn’t mean they don’t still have homework.

“I challenged our draft picks, rookies, all of them,” coach Jon Gruden said. “I challenged really the last three draft classes. We need to get more out of our young players here.”

Gruden, who was introduced as the Raiders coach in January, gave a particularly stern warning to his veterans: “If the young guys don’t start following you guys, you’ll be playing in all four preseason games.

“We’ve got some great role models. I want our young guys to stay on the gas pedal, be smart in what they do in the offseason and try to keep their football very close to them; keep studying, keep training and getting mentally and physically fresh. If we do that, we’ll have a chance.”

Gruden took a different tack with his staff.

“These coaches, they’ve been in there every day at 5 a.m. I go home at 7 p.m. and some of them are still in here every day. There’s been no May this year, no April. These guys need to be with their families — their wives, their kids, their families. And do some things maybe outside of football that they like to do.”

The Raiders hit the practice field in Napa at 9:15 a.m. July 27.