England manager Martin Johnson expects injured captain Lewis Moody, scrum-half Ben Youngs and prop Andrew Sheridan to return to action next week.
The trio are all set to be named in the 30-man World Cup squad Johnson will announce next Monday, and in the side to face Ireland in Dublin on 27 August.
"I am confident they will all go to New Zealand and confident they will be available next week," Johnson said.
Moody was forced off with a knee injury in the win over Wales on 6 August.
That prompted fears that he may struggle to recover in time to prove his fitness ahead of the squad's departure to New Zealand on 29 August.
Youngs, who is recovering from knee surgery in July, and Sheridan - who has had another shoulder operation after missing the last two matches of the Six Nations with a calf problem - did not feature in either of England's first two warm-up Tests against Wales.
Johnson would prefer to see them prove their match fitness in Dublin a week on Saturday, two weeks before England's opening World Cup match against Argentina on 10 September.
While Johnson says he has almost finalised his 30-man World Cup squad, he admits the identity of his first-choice side is still unclear after the failings exposed by Saturday's 19-9 defeat by Wales in Cardiff.
"We're pretty much there with our 30 for the World Cup, but in terms of the starting 15, there's still a little way to go," he told the RFU website.
"The two different sets of forwards have done pretty well over the two weeks and 27 players have started over the two Test matches and put themselves in a position to win them both.
"So there are some positives to come out of the Wales game, some bits that were OK and some bad that needs to be sorted out pretty quickly.
"We still get together next week and play one more game before going off to the World Cup, so I've not lost sight of the bigger picture here.
"But that doesn't help your emotions straight after a game like that. There are lots of things that we need to get better at."
Johnson's World Cup-winning team-mate Will Greenwood believes England need more creativity at centre rather than persevering solely with "big lumps" such as captain Mike Tindall, Shontayne Hape and newcomer Manu Tuilagi.
"I don't think you can carry three big lumps," said the 38-year-old, speaking at Twickenham to promote the second Help for Heroes benefit match.
"The balance isn't quite right. However, we're not on Mars here. We're round the corner from nailing it. I still believe that this is a very, very good England side, a very powerful England side."