Launchbury had been named in head coach Eddie Jones’ 23-man matchday squad for the clash but has failed to recover from a hamstring injury and will return to club side Wasps for further treatment.
The 24-year-old’s injury setback has earned Northampton’s Courtney Lawes, who was initially overlooked, a reprieve and he is set to compete with Itoje for a place alongside George Kruis in the second row.
Itoje made his England debut off the bench during their 40-9 victory against Italy in Rome earlier this month and, given Lawes’ initial omission from the squad, is the prime candidate to start.
“It’s a competitive position right now and that’s a good thing,” said England forwards coach Steve Borthwick. “We’ve got a mixture of players there with different levels of experience.
“That’s a really good thing for the squad to make that a competitive area. With that it spurs the intensity of training.”
England will return to Twickenham on Saturday for the first time since a 33-13 defeat to Australia in October consigned them to World Cup failure as they became the first host nation in history to suffer a group-stage exit.
Full-back Mike Brown insists the spectre of the World Cup remains a constant presence but provides him with an added incentive to succeed in an England shirt.
“I will always have it there at the back of my mind to motivate me even more,” said Brown. “Every single day, every time I am training, every time I’m playing, every time I’m lucky enough to pull on a white jersey.”
England remain on course for their first Six Nations Grand Slam since 2003 after victories against Scotland and Italy, while Ireland’s hopes of an unprecedented third successive title will disappear with defeat at Twickenham.