Sol Campbell has defended Rio Ferdinand's decision to withdraw from the England squad, and believes the Manchester United defender still has an international future.
Ferdinand, 34, had been included in Roy Hodgson's squad for the World Cup qualifiers against San Marino and Montenegro, but withdrew to follow a pre-planned fitness routine designed to help him manage his long-standing back problems.
Ferdinand was widely criticised for his withdrawal, and he received further flak when he flew to Doha to be a pundit on Al Jazeera's coverage of the San Marino fixture.
But former England, Arsenal, Tottenham and Newcastle defender Campbell has leapt to the defence of his former team-mate.
He said: "I know what Rio is going through because international football does take a lot out of you.
"If you have a regime, a way of playing and a routine then playing for your country requires a lot more effort.
"If you are in a routine and happy with that and then you are looking to play another game it can be demanding on the body.
"Playing for England can put a lot of demands on your body. And then you have to get back and play for your club.
"If you haven't put that into your routine and no-one has told you that they are thinking about putting you in a month ago then it's hard to put it in."
And Campbell does not believe the current furore marks the end of Ferdinand's England career.
"He (Rio) said he would love to be involved in the next one," he added.
"It's just a crucial moment for England and Manchester United so it's a difficult for him to decide. It's physical. International football and the travelling is demanding.
"People need to talk and work it out. I think it was just a shock to Rio because he was thinking, 'Well, I haven't got a chance and then all of a sudden with a few injuries he had a chance.' It was surprising."
Campbell was speaking after watching Wales train ahead of their World Cup qualifier with Croatia, as part of completing his coaching badges.
He said: "Watching Wales train is all part of the learning process.
"I'm doing my B licence and I finish around June time and then I will start on my A badge.
"I'll know in three years time if coaching is something for me in the long-term."