Auckland - England announced on Sunday they were bringing Thomas Waldrom into their World Cup squad as a permanent replacement for injured prop Andrew Sheridan.
New Zealand born back-row Waldrom arrived in his homeland on Wednesday as precautionary cover for No 8 Nick Easter, struggling with a back problem.
But England, who picked five props in their 30-man World Cup squad, were not obliged to select a like-for-like replacement for Sheridan, whose tournament was cut short by a shoulder injury he suffered in England's opening 13-9 win against Argentina.
And even though utility prop Matt Stevens has an ankle knock, England manager Martin Johnson has decided to bolster his back-row options by selecting Leicester's Waldrom.
"Nick is making good progress as is Matt Stevens but with Thomas now out here it makes sense to get him into the squad officially so he can join in with training," Johnson said in an England statement.
"We also owe it to Leicester to make a decision so that they can plan accordingly without him," former Leicester star Johnson, England's 2003 World Cup winning captain added.
Waldrom, a 28-year-old loose forward who joined Leicester from New Zealand's Crusaders in 2010, only discovered in March he qualified for England through his grandmother and is yet to be capped.
He was a member of England's preliminary 45-man World Cup training squad but was hampered by a calf injury and dropped out before the August warm-up Tests.
Easter hasn't featured since the Argentina match, with James Haskell taking over at No 8 during the subsequent Pool B victories, also at Dunedin's Otago Stadium, over Georgia (41-10) and Romania, who were thrashed 67-3 on Saturday.
England, bidding to reach a third successive World Cup final and fourth in total, meet Scotland in their final pool match at Eden Park this coming Saturday.
But should the Scots beat Argentina in Wellington on Sunday, both England and Scotland would have qualified for the quarter-finals before the latest edition of rugby's oldest international fixture.
Waldrom's inclusion was a setback for Leicester, who signed him in the belief he would not be needed for Test duty.
The Tigers, beaten 50-25 by English champions Saracens on Saturday, have now lost 12 players to the World Cup.