Safety Antoine Bethea is one of three players 35 or older in Giants training camp. He joined the exclusive club — with quarterback Eli Manning (38) and long snapper Zak DeOssie (35) — on the third day of practice.

“Ah man, he’s been in the league for a little minute,” defensive end B.J. Hill said while trying to guess Bethea’s age before practice. “I’m going to say he’s like 32? 33? 34? Wait, no, five? Yeah, he’s still young, though. He’s still got it in him.”

In early March, the Cardinals released Bethea, and just a few days later, the Giants signed the 13-year veteran to a two-year contract. He now reports to training camp in a leadership role on a young Giants defense.

“I think we can be one of the top [defenses] in the league,” Bethea said before the team’s first practice with pads. “I think they’re gelling together really well, but obviously we have to wait until we … get in front of some other teams, but so far so good.

“Everyone is taking everything in really well, and we just have to wait and see.”

Though he played nearly every snap on defense while appearing in all 16 games for the Cardinals last season, Bethea simply wasn’t the player he once was. It’s worth noting his 24 career interceptions are fifth among active safeties, sitting behind Reggie Nelson (38), Mike Adams (30), Eric Weddle (29) and Earl Thomas (28).

But the 5-foot-11 former sixth-round pick in the 2006 draft is looking to make an impact on a team that is struggling for a defensive identity.

“The way the league goes is next man up, whatever the situation is,” Bethea said. “Obviously, you don’t want those things to happen. As far as injury-wise, we play a physical game so that’s going to happen. For the young guys, it’s next man up.

“You have to look at the positive side — it’s an opportunity for somebody to come up and get in. As a team, we have to come together, ride together and be in it together.”