Ben McAdoo seemed pleased by Eli Manning’s preseason debut on Monday night.

“I thought he had a fairly good showing,” the Giants coach said of the 10-for-14 performance for 80 yards. “A couple of throws I think he’d like to have back, but that’s a part of it, especially in preseason.”

The rest of the offense, though, was far from that standard of “fairly good.”

“We left a lot of offense on the field,” McAdoo said. “Too many unforced errors. Not one guy. For us to have a chance, we need all 11 knowing what to do and how to do it.”

Starting running back Paul Perkins had six carries for 10 yards, including one for 16 yards. Simple arithmetic tells us that Perkins then spent a lot of time going backward.

“It takes everybody to run the ball, not just the offensive line,” McAdoo said. “The receivers have to be better versus slam corners. The tight ends, in line and from the backfield, need to do a better job. They weren’t even close yesterday. The running backs have to take the right footwork at the right pace and of course have to be on point and read their cues. We left some runs on the field yesterday from a running back perspective.”

Line change coming?

advertisement | advertise on newsday

Backup right guard D.J. Fluker played well on Monday night and may be in line for a promotion.

“We’re going to look at those options and talk through them as the week goes on and see how it shakes out,” McAdoo said of swapping Fluker for John Jerry with the starting group. “But we have not lost confidence in John Jerry or anybody on the offensive line for that matter.”

In fact, the Giants seem to be gaining confidence in at least one of their players: Fluker.

“He’s learning,” McAdoo said of the first-year Giant, a former first-round pick of the Chargers. “He’s playing a couple of different spots. He’s learning the offense still, he’s working hard through it. He’s a physical football player and when he gets his hands on somebody, he’s a physical man.”

Giant steps

NFL videos

The Giants have not made a decision regarding the future of T Michael Bowie, who during the weekend was charged with domestic assault and battery and two counts of malicious injury or destruction of property for an incident that took place this summer with his girlfriend. Bowie did not travel with the team to Cleveland and McAdoo said he is not sure if Bowie will be on the practice field Wednesday when the players return to work . . . McAdoo liked the effort from the defense on Monday night, embodied by one Olivier Vernon play in particular. “Look no further than OV’s example chasing an eligible receiver across the field and breaking the ball up,” he said of Vernon covering TE David Njoku 30 yards down the field and swatting the pass away for an incompletion. “Great effort there” . . . WR Tavarres King re-injured the ankle he rolled earlier in training camp.