England will be allowed to replace Wayne Rooney in their World Cup squad up until 24 hours before their opening match against Paraguay on 10 June.
Fifa confirmed that their regulations allow for a player to be substituted provided the governing body is supplied with evidence of serious injury.
If a replacement is called up Rooney would take no part in the tournament.
Eriksson has to name his 23-man squad for Germany on 15 May, but will announce a provisional squad on 8 May.
A Fifa spokesman told BBC Sport: "It's the same as any other Fifa competition.
"With a medical report, players who are on the official list, as of 15 May can be replaced up to 24 hours prior to each team's first match."
Eriksson has said he will take Rooney even if there is just a possibility of playing him in the tournament.
Rooney suffered the injury in United's 3-0 defeat at Chelsea, following a tackle by the Blues' Portuguese defender Paolo Ferreira, for which no foul was given.
"It was an innocent tackle, obviously I didn't intend to hurt him," Ferreira told Portuguese television.
Two years ago Rooney broke another bone in the same foot, playing for England against Portugal at Euro 2004, and was sidelined for 10 weeeks.
This injury happened six weeks to the day before England's opening World Cup Group B match against Paraguay at 1400 BST on 10 June.
England also have concerns over Rooney's strike partner Michael Owen and defender Ledley King, both of whom have also broken bones in feet.
Ashley Cole and John Terry are expected to be available for the trip to Germany despite the Arsenal left-back having just returned from injury and the Chelsea centre-back damaging an ankle over the weekend.