West Ham's Matthew Upson believes he will be the man to benefit from any problems with England's first-choice central defenders at the World Cup.
In recent weeks, Tottenham duo Ledley King and Michael Dawson have both been identified as possible alternatives for England coach Fabio Capello.
Captain Rio Ferdinand continues to be troubled by a long-running back problem at Manchester United, while the form of John Terry for Chelsea has been widely criticised.
However, Upson still believes he is the man to benefit from any problems with Ferdinand or Terry in South Africa.
"Going on the last few internationals I would have to say I do feel like I am the next in line," he told BBC Sport.
"But football changes very quickly so you can never rest back and take that for granted, so I think it's important you keep on top of your game and keep wanting to improve to secure your place."
Upson has won 31 England caps since making his international debut in 2003.