Liverpool captain Gerrard announced his retirement from the international scene last month, after 14 years' service with the national side.
England's World Cup squad had a distinctly youthful feel, with Roy Hodgson taking an inexperienced group of players to Brazil.
"Let's face it, you can never replace a player like Steven Gerrard because he's probably the best player this country has ever seen - so yes, he's irreplaceable," Henderson is quoted as saying by The Mirror.
"I don't think you even necessarily try to fill that void.
"He is a one-off, I see him every day [at Liverpool] and I don't think there is any player like him.
"But what we have to do is develop the young talent coming through, and there is a lot of it.
"We've got to give them space to go and show how good they are.
"The likes of myself, Jack [Wilshere], Ross [Barkley] or whoever is in the England team need to take more responsibility, step up to the plate and take more of a leadership role if needed. The group will work on that, whoever that will be."
