FLORHAM PARK, N.J. — At the first team meeting of OTAs, New York Jets running back Braelon Allen waited with his fellow rookies for the veterans to find their seats in the auditorium — one of those unwritten rules that newbies must abide by.

Once the vets settled in, Allen located Aaron Rodgers, walked to his seat and introduced himself. The 40-year-old quarterback knew Allen’s backstory, how he started for Wisconsin at the age of 17 and now was the youngest player in the NFL.

“He was definitely a little tripped out about [my age] when I first met him,” said Allen, now 20. “He was like, ‘[You’re] the first guy I ever played with that could literally be my kid.'”

It’s not just Allen; youth is spread across the entire backfield.

The franchise that produced the oldest NFL rushing champion in history — Hall of Famer Curtis Martin, 31, in 2004 — now has the youngest running back room in the league, according to ESPN Stats & Information (based on rosters as of Aug. 9).

The average age? 22.8 years.

Call them Generation Z4, with Breece Hall (23), Allen, Isaiah Davis (22) and Israel Abanikanda (21) — the top four backs on the depth chart. Also on the roster are Deon Jackson (25) and Xazavian Valladay (26). Only three, maybe four, will make the opening-day roster.

When Rodgers hands off the ball this season, it will be to someone not old enough to remember Rodgers’ rookie season … way, way back in 2005. Heck, Allen was only three months old when Rodgers was drafted.

Hall, by far the Jets’ most accomplished player at the position, finds it strange every time running backs coach Tony Dews refers to him as the one “everybody looks up to.” Hall doesn’t see himself as the dean of the running backs.

“Everyone in the running back room is pretty much around my age,” Hall said. “So it’s like the funniest thing.”

This represents a shift in philosophy for the Jets, who spent big money last summer on Dalvin Cook, who was 28 when he signed a one-year, $7 million contract in the preseason. Maybe they learned a lesson about past-their-prime runners, as Cook was held to 3.2 yards per rush on 67 attempts. They cut him before the season was over.

This spring, the Jets drafted Allen in the fourth round, then doubled down by taking Davis in the fifth out of South Dakota State. Both have impressed in training camp, especially Allen, a 6-foot-1, 235-pound bruiser who could be the ideal complement to the speedy Hall.

“Coach Dews kind of coaches him a little different than he coaches us because he’s more of that Derrick Henry-style of running back,” said Hall, who ran for 994 yards last season and added 591 as a receiver.

In Saturday’s preseason opener, Allen probably solidified the RB2 job, rushing for 54 yards on six carries against the Washington Commanders. Coach Robert Saleh called him “a very heavy runner,” adding, “When he got to the second level, it’s painful to just touch the human.”

There’s no doubt that Hall is the No. 1 back, capable of making an impact on all three downs, but the Jets will look to spell him. Right now, Allen is the top backup. Hall joked that they’re calling themselves the “Killer Bs.”

After graduating early from high school, Allen rushed for 3,494 yards and 35 touchdowns in his three-year career at Wisconsin. Initially, he was recruited as a linebacker. They also talked about making him a safety. He wound up on offense, making an impression on Rodgers, who caught the Badgers on TV and noticed this 17-year-old tailback bulldozing Big Ten defenses.

Allen grew up Fond du Lac, Wisconsin, not far from Lambeau Field, home of the Green Bay Packers. As he said of Rodgers, “I grew up less than an hour away from where his name will live on forever.”

Funny thing is, Allen’s parents are Chicago Bears fans.

“So the household was pretty bitter on Sundays twice a year,” he said, laughing.

The Jets made Allen (20 years, 98 days) the third-youngest player drafted into the NFL since 2000, according to the Elias Sports Bureau. The only younger players were defensive tackle Amobi Okoye (19 years, 322 days) in 2007 and linebacker Tremaine Edmunds (19 years, 359 days) in 2018.

Allen knows his role in the backfield.

“I’m kind of the outlier in the way of size, so I know what I’m here to do — and that’s to play smashmouth football,” Allen said.

Davis (6-1, 220) is closer in style to Hall than Allen. He’s not as fast as Hall, but he’s an instinctive runner with enough speed to get to the edge. He dominated on the FCS level, rushing for 4,548 yards and 50 touchdowns over four seasons.

He was the Gatorade High School Player of the Year in Missouri, but he was a no-star recruit with only one Division I offer — South Dakota State. Actually, it was only a 65% scholarship until late in his freshman year, when the school bumped it up to a full ride.

Davis considers it a blessing to be in the NFL, competing for playing time as a rookie. His ability to return kickoffs and punts could be his ticket to a prominent role. His highlight in the preseason opener was a 24-yard reception.

“It’s a competitive group, a lot of guys who are hungry,” Davis said.

Leaguewide, the value of running backs has declined in recent years, but general manager Joe Douglas has picked at least one in each of his five drafts. Four remain on the roster — Hall, Allen, Davis and Abanikanda, a fifth-round pick from Pitt in 2023. Abanikanda scored on a 2-yard run against the Commanders.

It’s still early, but the Jets appear to have good depth at a young man’s position.

“It’s come a long way since the first year we were here,” said Saleh, who was hired in 2021. “We feel like we’ve got some legitimate runners all across the board.”