Ryan Nassib is the backup quarterback for the Giants slotting in right behind starter Eli Manning.

At least he is for a night.

Nassib the rookie from Syracuse gets the call Thursday night against the Patriots at Gillette Stadium after Manning and the first-team offense get in the 12-15 plays coach Tom Coughlin wants to see from the starters. Figure Nassib stays on the field at least until halftime and perhaps into the third quarter before David Carr and then Curtis Painter finish up in the preseason finale.

If all goes according to the best-laid plan of the Giants the snaps Nassib gets will be the last ones he gets as the hope as spelled out rather succinctly on draft day by general manager Jerry Reese is that Nassib never sees the field.

“If he doesn’t ever play that would be great’’ Reese said back on April 27 when the Giants traded up in the fourth round of the NFL Draft to take a player Reese projects at least initially as “a terrific backup.’’

Nassib started 38 games at Syracuse and threw 1312 passes and the thought that after he gets his work done in Foxborough Mass. he never will be seen again is well a bit strange for him to consider.

“Someone did bring that up to me last night’’ Nassib said Tuesday after practice. “It was kind of weird to think about. It’s just the way the situation is I’m cool with that. I just have to make sure I take these reps as serious as possible because they might be my only reps for some time. We’ll see.’’

The absolute best-case scenario for the Giants this summer was for Nassib to show so much in his first training camp that Coughlin felt secure in keeping only two quarterbacks on the roster something he prefers to do. That was always an unlikely plan which is why Carr and Painter are fighting for the No. 2 quarterback job with Nassib safe when final cuts come in Saturday set as No. 3.

None of the quarterbacks have gotten much accomplished because the Giants can’t score touchdowns (they have two in three preseason games) and cannot mount drives (they have converted 12-of-49 third downs — 25 percent). Manning’s rating is 60.3 Carr is at 78 Painter is 59.9 and Nassib is 59.2. The rookie has completed just 3-of-10 passes for 53 yards. In practice he has fired numerous interceptions though not as many lately.

Other than going out and pitching a perfect game Nassib is most likely not going to be able to convince Coughlin that he’s ready to be the only other quarterback on the roster.

“As a competitor I feel I’ll be ready to play any day’’ Nassib said. “You got to prepare like that. Am I confident in my abilities? Sure. Would I be disappointed if I’m not the backup? No because I can understand why. You got to be ready to play whenever.’’

One possible move for the Giants is to cut Carr and Painter and have one of them — most likely Carr as he knows the entire offensive system — waiting in the wings in case anything happens to Manning. It is unlikely another team immediately will scoop up either Carr or Painter.

But what if Nassib is the only other quarterback on the roster and he’s needed in a real game?

“The game plan might need to adjust a little bit to where it’s not as sophisticated as the ones with Eli’’ Nassib said. “But I would try my best to try to operate as best as we can so the game plan won’t have to change that much.’’