The Giants need a better Marshall plan.

They had one of the top receivers in the NFL over the past decade on the field with them Sunday night in Dallas and treated him like an interloper at a cocktail party. He was targeted just four times in the 19-3 loss to the Cowboys and did not make his first catch as a Giant until the game’s final play.

“I think it was a product of a lot of things,” Ben McAdoo said Monday of the lack of production — and attention from the quarterback — for Marshall. “There may have been times when we were trying to get him the ball, couldn’t get him the ball. It’s not one factor. It was a variety of things. We certainly wanted Brandon to get a touch before he got a touch.”

Afterward, Marshall said he was more disappointed by the loss than his statistics.

“I’m not worried about that,” he said of coming perilously close to his first game without a reception since his rookie season in 2006. “I’m more worried about our offense being more efficient and starting faster.”

No Odell surprise

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Eli Manning said Monday on WFAN that he was not surprised Odell Beckham Jr. did not play against the Cowboys.

“I didn’t think he was going to play,” Manning said. “He didn’t practice all week, he hadn’t practiced in three weeks. It’s tough for a guy not to practice in three weeks and show up and play on Sunday. He hadn’t run routes, he hadn’t really done much of anything.”

The Giants decided to hold Beckham out following a workout on the field with teammates that included his first passes caught from Manning since the Aug. 21 ankle injury.

“He ran some routes pregame and did some things, so I guess there was a chance he was going to go,” Manning said. “But it would have been tough.”

Giant steps

Asked about making changes to his beleaguered offensive line, McAdoo said: “We’re confident in the guys we have. If we feel we need to make a change, we’ll make a change.” . . . RT Bobby Hart (ankle) and CB Janoris Jenkins (hand) were injured in the game. McAdoo did not say how serious they are . . . McAdoo continued to describe Beckham as day to day and would not say if he will return to practice this week. The Giants aren’t back on the field until Thursday . . . WR Roger Lewis Jr. said he thought the fourth-quarter interception by Cowboys CB Anthony Brown would be reviewed. “I had the ball,” Lewis said of the play in which Brown seemed to make the initial catch but he and Lewis had their arms wrapped around the football. “I thought we were going to get the ball back,” Lewis said. All turnovers are reviewed, and this one seemingly passed muster without officials needing to take a closer look.