Ben McAdoo said he envisions his starters playing about 15 snaps on Friday in the preseason opener. After that, it’s every man for himself as far as snap count goes.

“We’re going to be consistent,” McAdoo said Tuesday. “We’re going to treat every guy differently.”

In other words, Eli Manning and Odell Beckham Jr. may not be on the field as long as, say, rookie safety Darian Thompson, who is penciled in as a starter.

“We’re going to take every player case by case . . . based on what we need to see and what we want to see,” McAdoo said. “We want to see guys competing for jobs. That’s what the preseason’s all about. We have to put guys in position to be successful and see if they’re going to compete and win jobs.”

Health club

After a stunning streak of mostly injury-free days at training camp, the Giants’ luck may have caught with them a bit. Besides Victor Cruz being pulled with a tight groin, the Giants were also without linebacker Keenan Robinson (groin) and safety Nat Berhe (hamstring). Fullback Nikita Whitlock left practice early with an illness.

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The Giants did still seem to have their health mojo when it mattered most, though, as two defensive starters were hurt but returned to the field after evaluations. Safety Landon Collins was kicked in the left ankle and defensive end Jason Pierre-Paul suffered a burner.

Giant steps

Rookie WR Sterling Shepard’s confidence is high heading into his first preseason game. “If I run my routes correctly then I’m going to be able to take it to the house,” he said . . . A day after the offense dominated by scoring twice in a pair of two-minute drills, the defense stepped up and stopped three such drives . . . Rookie LB Ishaq Williams, a converted defensive end, made two nice plays on consecutive snaps and seems to be adjusting to his new position. McAdoo said Williams will be “an interesting guy to see play in the game.” . . . CB Eli Apple, the youngest man on the roster, turned 21 on Tuesday.