What the hell are the Giants going to do?

They no longer have Saquon Barkley, and behind capable replacement Devin Singletary is a trio of inexperienced running backs with no NFL experience whatsoever.

How can this team figure out if any of these guys can play at a high enough level to compensate for the loss of one of the league’s best running backs to free agent?

“Just let them play,” coach Brian Daboll said. “That’s what they have to do. We talked about it. I think I got a lot of questions early on about how young the team is. Let them play.”

That’s about all the Giants can do, right?

Let them play and see what happens.

A single preseason game doesn’t say much, but the Giants would like to believe that Thursday’s 14-3 win over the Lions at rainy MetLife Stadium at least gives an indication of the potential of the players assembled in the running back room.

Singletary was on the sidelines with the other starters on offense, and the three running backs used by the Giants all made a solid or better impression.

The competition to secure roster spots and solidify a spot as the No. 2 running back behind Singletary is on, and all three have done their part.

Eric Gray looked like a different player after an unremarkable and uninspiring rookie year when he ran for a 48-yard touchdown run.

In addition, he plowed into the end zone with a 1-yard touchdown run and caught four passes for 46 yards, including a lob from Tommy DeVito that he caught over the shoulder for 24 yards.

Undrafted rookie Dante “Turbo” Miller led the team with 12 rushing attempts and 63 yards, an average of 5.3 yards per attempt.

Another rookie, Tyrone Tracy, selected in the fifth round, ran for 26 yards on his five attempts and averaged 5.2 yards per attempt.

“I thought they were determined,” Daboll said. “I thought they weren’t very stumbling. I thought they hit the hole with good vision. They ran in space. Gray had a nice catch from Tommy there. It wasn’t perfect, but most of the time they were going forward. They ran hard. They laid down their pads. They did a good job for the first game.”

Barkley was selected number 2 in the 2018 NFL Draft and his physical talent is undeniable.

When healthy, he averaged 1,307 and 1,312 rushing yards in those seasons.

His lower body is massive and powerful, and yet there were moments when the Giants were frustrated by Barkley’s perceived lack of conviction at the line of scrimmage.

It is therefore interesting that, when analyzing the work of his three young defenders, Daboll spoke of “determination” and the absence of “much stuttering.”

Miller, a graduate of Columbia University and the Ivy League, ran for 19 yards and expressed relief that his training camp indoctrination had paid off in preparing him for the challenge of a preseason game.

He praised Daboll, first-year running backs coach Joel Thomas and new special teams coordinator Michael Ghobrial for their expertise.

“Coach Dabes and coach Joel Thomas, coach Gobes, all of our coaches prepare us to be in the best situations to play on game day,” Miller told the Post. “When I was out there, I was like, ‘Damn, they really did that. I know exactly what’s going on, I know the reason we’re doing things, the plan.’ It wasn’t too much because they prepared us for it. It’s a blessing to be coached by great coaches.”

The Giants ran 155 yards, with the game utilizing the second and third team offensive lines.

There were no glaring errors, which is a plus when young players are on the field for the first time during pre-season.

Miller was called for a holding offense in pass protection, but the Lions denied it.

“I thought they did a good job of protecting and knowing who to block,” Daboll said. “It wasn’t overly complicated, but they put their face in there, closed the window and blocked some blitzes. They ran hard. They knew what to do. Again, it’s going to be tough competition for all these young players, but I think Joel Thomas has done a fantastic job of developing that youth room.”

Barkley now plays for the rival Eagles and it is a shock for the Giants to see him leave.

Gray is currently the only running back who was on Barkley’s team last year, and his absence cannot be ignored even if Singletary is wearing Barkley’s No. 26 jersey.

“Everyone has the feeling that you’re saying,” Gray said. “I think everyone has done a great job. Whether you’re young and learning the system or like me, you’re a second-year player in the system just getting comfortable and being yourself.”