The England coach, who names his team next week, is confident that the injured trio will be fit in time for the tournament in New Zealand.
“In terms of where they are at the moment, they’ve got the medical guys and the strength guys out with them and they’re working hard so I’m confident they’ll all be available to be picked next week," said Johnson.
“We’ve reviewed everything as we’ve gone along and we’re happy that we’ve done everything we can up to this point.”
Captain Moody picked up a mild ligament strain during England’s 23-19 defeat over Wales earlier this month, while scrum half Ben Youngs and prop Andrew Sheridan have both been sidelined during the warm-up series with knee and shoulder knocks respectively.
Johnson will name his 30-man World Cup squad on Monday, August 22.