If Daniel Jones can help cure what ailed the Giants in their season-opening flop, by all means, get him on the field, and not merely in run-out-the-clock mode. Get him up to speed and get him out there at the start, hoping his young legs and athleticism can help with the tepid pass rush and the terrible pass coverage.

Unless Jones can do something to improve a defense that went from worrisome to frightening with one sorry performance, he is exactly where he needs to be. That is, on the sideline, waiting his turn.

Quarterback is the most important individual position in team sports and having one, versus searching for one, is the NFL’s most definitive line of demarcation. Building a winning team, though, goes way beyond securing the guy behind center on offense.

The Giants, after winning eight games and losing 24 the past two seasons, are in rebuild mode. They believe they have their future starting quarterback. But if they do not have a competent defense and do not have a breakout player on offense, other than Saquon Barkley, they are not and will not be a winning franchise.

The 35-17 loss to the Cowboys was remarkable in that it had so very little to do with Eli Manning.

Think about that. Did Manning do anything that either devastated or delighted you? He completed 68 percent of his passes for 306 yards, threw one touchdown pass and did not throw an interception. His brightest moment came in the third quarter, when, about to get sacked by Dorance Armstrong, he somehow kept his balance with his left arm, barely preventing his knee from touching the turf to kill the play, steadied himself and fired downfield to Cody Latimer for 22 yards.

Four plays later, from the Dallas 7-yard line, Manning looked bad on an ill-fated rollout pass play on fourth down that was instantly sniffed out by the Cowboys. With nowhere to go with the ball, it did not even matter that Manning was sacked by DeMarcus Lawrence and lost the ball on a fumble, as the failed conversion meant the Giants were going to lose the ball on downs, anyway.

Again, did anything there surprise anyone? Manning made the play with his arm and then did not make the play with his legs.

Manning at 38 is a more-than-competent quarterback — his passer rating of 95.5 in the opener was higher than his career mark of 84.1 — capable of directing a game just fine, unless he is required to do more than that. It was 28-10 early in the third quarter and Manning is not going to be a comeback kid at this stage of his career.

So, why waste time with him? Let Jones, the rookie, take his lumps right now, fast-forwarding the development process? Well, this season is about a whole lot more than getting Daniel Jones ready to start in 2020. It is far more about projecting whether general manager Dave Gettleman and head coach Pat Shurmur are capable of turning this listing ship of a franchise out of the losing storm and into winning seas.

It does the Giants no good to get Jones on the field now if they take the same shabby defense into next season. It is true that Manning in 2004 took his lumps, going 1-6 as a starter and those lessons and growing pains helped him immensely in his second season. It is also true Ernie Accorsi, the general manager at the time, was assembling a defense that would eventually muscle its way to not one, but two Super Bowl titles.

By the time Manning took over in 2005, he was bolstered by having as teammates Michael Strahan, Osi Umenyiora and Antonio Pierce, plus rookie defensive players Justin Tuck and Corey Webster. The main ingredients were in the pot for an appetizing defensive meal.

Jones is the centerpiece, but not the only piece, of a young core that will define this regime. Rookie Dexter Lawrence was quiet in his first NFL game and rookie DeAndre Baker was loud, as in bad, in his debut.

These are first-round picks that must be hits, not misses. The same with Lorenzo Carter, B.J. Hill, Oshane Ximines and Julian Love, all first- or second-year defensive players picked by Gettleman and coached by Shurmur and defensive coordinator James Bettcher. The same with Jabrill Peppers, a key part of the trade that sent watch-wearing Odell Beckham Jr. to Cleveland. This is the guts of a defense that will determine how this regime is remembered.

Jones is a huge part of it, of course, but far from the only part of it.