With John Terry ruled out of the clash in Lisbon with a hamstring injury it is between Ledley and Liverpool's Jamie Carragher to partner Sol Campbell. Terry is expected to be fit for the second group game Switzerland next Thursday.
Eriksson said: ""Jamie Carragher is more experienced with international football, but Ledley King is maybe a little bit quicker and a better header.
"You can't give someone experience, the only way is to play them. I'm not worried about it though as he seems to be very calm. I don't think he's a nervous person.
"You can never be sure when you meet Thierry Henry, of course, but I think - and hope - that we are ready.
"We must keep our shape though. If you don't have that, you must go home - especially against France. If they find space, they will kill us on the counter-attack."
Sven Goran Eriksson has insisted he has no worries about plunging Ledley King in against France in England's Euro 2004 opener tomorrow.