Roger Lewis Jr. came back from the bye last week and heard a message from his coaches.

“It’s time to go.”

He didn’t know exactly what that meant at the time. Now he does. Now everyone does.

Sunday’s 28-23 win over the Eagles was the debut of the Giants’ retooled personnel on offense and defense coming off the bye week, and most of the changes were focused on increasing the playing time of their youngest players. Two of the Giants’ four touchdown passes were caught by rookies — Lewis, an undrafted one, and Sterling Shepard, the second-round pick. The leading rusher was rookie Paul Perkins. Undrafted rookie Andrew Adams had a key interception in the first quarter. Even B.J. Goodson, the “linebacker of the future” for the Giants, saw his first three defensive snaps.

The Giants totaled 219 snaps on offense and defense from undrafted players in their first or second year with the team, most of whom played their largest role of the season.

Youth, they say, is wasted on the young. The Giants don’t seem to want to waste any of theirs.

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Big Blue is now Gang Green.

“That’s how I grew up in this business, to get young players and everyone [who’s active] involved in game days,” Ben McAdoo said. “Give them all the support they need to be successful. The way to get young players acclimated to the varsity team is to get them out there and get them going. When the snaps get to December and January, it’s not too big for them. It’s not the first time they’re on the field.”

That’s the plan, anyway. The Giants are 5-3, second in the NFC East and, at the moment, the NFC’s first wild card. They need those unripe players to season and continue to get better.

The philosophy is a departure from how the Giants operated for most of their recent failed history. Tom Coughlin was slow to trust rookies and often relied more on veterans who were closer to the end of their productivity. McAdoo believes more in going through growing pains now for the benefit of the future. He’s been willing to accept miscues such as Perkins’ sometimes suspect pass protection, costly special-teams penalties by Adams and Lewis, and other infractions that would have landed a player in Coughlin’s doghouse.

“You have to acclimate them early,” McAdoo said. “You can’t wait until December. You have to get them opportunities to compete in practice and get them in there in games.”

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It’s not automatic. “They have to earn the opportunity,” he said. “They have to prove they’re trustworthy and accountable.”

Not all of it is by design. Adams played because the two safeties ahead of him were hurt. Brett Jones likely will be the right guard in place of injured Justin Pugh for a few weeks. Lewis was playing a larger role Sunday even before Victor Cruz left with an ankle injury.

And those are just the new young guys. Second-year safety Landon Collins is the only NFL player leading his team in tackles (69), sacks (three) and interceptions (three). Odell Beckham Jr. turned 24 last week.

Conversely, on a weekend when the Giants turned back the clock both on Daylight Saving Time and their roster, first-round pick Eli Apple was benched for the worst performance of his short career. “We’re going to dust Eli off, put him back out there,” McAdoo said. “He’s going to get better and learn from it.’’

The Giants believe 35-year-old Eli Manning gives them an edge over the Eagles and Cowboys, who both start rookies at quarterback. That may be the case. But Sunday showed that having good young talent around the wily veteran may be the best advantage.

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“I think it does a lot for your team,” McAdoo said. “It gives 46 guys an opportunity to play. I think it breathes some life in the veterans in the long season. There are young guys champing at the bit. They bring excitement and energy. It’s fun to see the young guys have success.”