Matthew Upson insists he is good enough to play for England – even though he will have to depose either the captain or vice-captain to earn a regular place in the team.

Upson – despite an unsteady display in the 5-1 defeat of Kazakhstan on Saturday – seems likely to win his 11th cap on Wednesday after John Terry was ruled out of the Group Six World Cup qualifier with Belarus having failed to recover from a back injury.

Upson, 29, appears to have won the confidence of Capello should anything happen to Terry or Ferdinand, though the former Arsenal defender does not regard himself as a mere stand-in any more.

"Maybe previously I have not believed in myself enough," the West Ham United defender said. "I did not think I deserved to be here. But when you feel like that, you only end up going one way. Now I do believe I deserve to be here. I think I can step in and do the job.

"Just because John Terry is the captain and Rio Ferdinand is the vice-captain does not automatically mean they are going to get picked.

"Things change very quickly in football. You get injuries and loss of form. It doesn't matter what someone else is doing, it is about how I am playing and I have to make sure I am ready."

Upson must feel quietly confident of playing a major role in England's bid to reach South Africa in two years' time. While Ferdinand's absences are rare, Terry has been a more frequent visitor to the treatment table in recent times.

The Chelsea captain was missing on a number of occasions during the ill-fated Euro 2008 qualifying campaign, most notably against Russia in Moscow and Croatia at Wembley, both matches which ended in defeat when a draw would have got England into the finals.

Not long ago, England appeared well served with capable stand-ins in central defence. Jonathan Woodgate, Ledley King, Sol Campbell and Jamie Carragher were all adequate replacements with plenty of experience at the highest level.

But slowly that strength in depth has disappeared. The fitness of King and Woodgate cannot be relied upon, age has finally caught up with Campbell, while Carragher was not prepared to sit on the bench forever and promptly retired, claiming he was not bothered about playing for England in the first place.

Aside from Upson, Everton's Joleon Lescott is the other central defender in Capello's squad, with Wes Brown earmarked for the right back role. Then there are a crop of highly-promising youngsters – the under-21 duo of Steven Taylor and David Wheater, plus Micah Richards, three names who perhaps do not yet quite inspire the confidence required to perform flawlessly at international level.

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