Injuries in central defence including the late withdrawal of Sol Campbell and John Terry mean Ledley and Gareth Southgate are the only recognised central defenders in the 22-man squad.
The irony of it all is of course that Ledley has excelled in his new role in midfield this season.
Nevertheless, coach Eriksson suggested on Tuesday evening that Ledley will start alongside Southgate and earn his third cap.
Eriksson said: "We're a bit unlucky to be without four extremely good central defenders - not only in England, but the world.
"But it will be good to see other players. I think Ledley King is ready - but we will see tomorrow.
"With the exception of Ferdinand, I hope to have them ready for the Sweden game (on March 31) and before the tournament because it's important to know exactly which two defenders are going to be starting in Euro 2004.
"I have some ideas if I have everybody available - but tomorrow will be different, those two have not played together."
Sven Goran Eriksson has dropped a broad hint that Ledley King will make his first England start in Wednesday night's friendly against Portugal.