Manchester United defender Rio Ferdinand has been ruled out of England's opening 2010 FIFA World Cup South Africa™ qualifier against Andorra here on Saturday after failing to recover from a back injury.

Coach Fabio Capello said he thought Ferdinand would probably be fit for Wednesday's crunch clash against Croatia in Zagreb.

"We have only one serious injury. That is Rio. He will not be ready for the game on Saturday. He should be fit for the Croatia game," Capello said.

In the absence of the United stalwart, skipper John Terry is likely to be partnered at the heart of the defence on Saturday by either Matthew Upson or Joleon Lescott.

Terry admitted Ferdinand's absence was a real blow but the Chelsea star is confident either Upson or Lescott will prove a capable deputy for the England vice-captain.

"It's a big blow. Obviously he has been on fire for the last couple of years and at the start of this season as well," Terry said. "He'll be a big miss but we've got the squad and strength in depth to replace Rio."