Despite making an impressive start to the new Premier League season, the former under-21 international was overlooked by Gareth Southgate when he named his squads for next month's Euro 2020 qualifiers against Bulgaria and Kosovo.
Although Southgate selected Jordan Pickford, Nick Pope and Tom Heaton ahead of Henderson, who is on loan from Manchester United.
But John Egan, the Republic of Ireland defender, insists it is only a matter of time before the 22-year-old wins his first senior cap.
"It wouldn't surprise me at all (if Henderson is picked)," Egan said. "If you look at the England goalkeepers, Deano is right up there. It's not a case of 'if', for me it's a case of 'when' for Deano. He's got a really bright future ahead of him and, so long as he keeps his head down and keeps doing what he's doing, he'll get there."
Henderson enters tomorrow's game at Chelsea hoping to keep his second clean sheet of the season. With Southgate watching two of United's opening four matches in person, United manager Chris Wilder earlier this week challenged other members of his team to force themselves into contention, with Jack O'Connell among those being touted as a potential future call-up.
"I'll keep on looking after him (Henderson) and make sure he doesn't have many saves to make," Egan said. "If we can help him do that, then that should get him in there."