England remain hopeful that back-row trio Mark Wilson, Tom Curry and Sam Underhill will all be fit to face Ireland at Twickenham on Saturday.
England want all three available to take on Ireland to offset any need to pitch Billy Vunipola into a third Test in as many weeks.
Wilson has been carrying a rib complaint, Curry a shoulder concern and Underhll an ankle problem, but all three trained on Wednesday at England's Pennyhill Park camp.
"Those guys trained, trained well, and we'll continue to monitor them as training progresses," said forwards coach Steve Borthwick.
"We've got tonight and tomorrow morning (Thursday) as well before naming the team."
Lewis Ludlam is unavailable this weekend, undergoing a week's active rest as part of the deal between the Rugby Football Union (RFU) and the Premiership clubs.
The Northampton flanker's absence increases the need for Wilson, Curry and Underhill to be available, and ease any injury glut for head coach Eddie Jones.
Worcester hooker Jack Singleton covered back-row in England's home and away matches against Wales, as boss Jones prepares for the realities and constraints of the 31-man World Cup squad.
England will hope not to have to be stretched to that extent this weekend however, even in the enforced absence of Ludlam.
Maro Itoje and Courtney Lawes are also further options to slot into the back-row should either lock be required to step out to a loose-forward role.
Mako Vunipola is expected to feature after recovering from hamstring surgery, with Borthwick admitting the British and Irish Lions prop offers England a significant boost.
England have rarely been able to field their full-metal jacket power quartet of Mako and Billy Vunipola, Itoje and Manu Tuilagi.
All four are fit and ready to fire now, though, with Borthwick admitting that group can alter England's attacking dynamic.
"We want all our players available, and Mako's a world-class player and we're very fortunate to have three tremendous players in that position," said Borthwick.
"All those four players are very good, clearly top-class players.
"We're very conscious of the combinations you have together, the players you put together fitting the gameplan you want.
"And that again comes back to the plan we've got in building through these four games and into the World Cup."
