Jakob Johnson impresses in Giants preseason debut after receiving playbook 30 minutes before flight

HOUSTON — Jakob Johnson received his playbook about 30 minutes before the Giants’ flight out of New Jersey was wheels up.

Twenty-five hours later, without the benefit of a single practice with his new team, Johnson was on the field for eight offensive snaps Saturday during the Giants’ 28-10 preseason loss to the Texans.

“I got a lot of practice cramming for exams in college,” the University of Tennessee product told The Post, “so I feel I used some of that to make this work.”

Besides, what is the call for clearing a path with a bone-jarring block?

That’s what fullbacks like Johnson are supposed to do — and exactly what he did in springing Eric Gray for a 13-yard run.

“You don’t need a playbook for that. You buckle up your chinstrap and hit somebody,” Johnson said. “It’s a blessing because you spend so much time preparing for a moment that might come, might not come.”