Former England striker Stan Collymore has told Rio Ferdinand that he should consider his international future following his withdrawal from the squad earlier today.

Manchester United defender Ferdinand decided to pull out of the upcoming World Cup qualifiers against San Marino and Montenegro because of the "detailed pre-planned training and medical programme" that he has in place to manage his previous back injuries.

With that in mind, Collymore has raised concerns as to whether the 34-year-old would be able to cope with the limited rest periods between matches at the 2014 World Cup in Brazil.

"If training regime is strict, forget WC 14 in Brazil. More intense than San Marino /Montenegro. Try Argentina /Nigeria within a few days," Collymore wrote on Twitter.

Despite his omission, Ferdinand has insisted that he will continue to make himself available for selection to manager Roy Hodgson.