He can, indeed, “do a job” but can he do it well, can he do it under the pressure of a World Cup? Can he do it in a semi-final against Brazil?

These are the questions Fabio Capello needs to be asking himself as he prepares to name his 30-man provisional squad later today — followed on June 1 by his 23 to travel to South Africa — if he is not to make the same mistakes as some of his predecessors.

Take right back, which is one of the Italian’s many headaches. Carragher’s return is, we are told, not just a boon for England because he is a redoubtable centre half (which he undoubtedly is, and should travel in the 23 as such) but because he can cover for Glen Johnson.

But here’s how Carragher’s versatility worked at the last World Cup when he went to Germany as back-up to Gary Neville. When the Manchester United right back was injured, Carragher was summoned for the second game, against Trinidad & Tobago.

After that performance, Sven-Göran Eriksson decided that Carragher was not really a right back after all — certainly not the type of roving one he needed — so he offered the job to David Beckham. When the captain declined the offer, thinking it was not really the time to experiment mid-tournament, Eriksson turned to Owen Hargreaves.

Neville eventually returned to resolve this mess but only after Carragher, who travelled as reserve right back, had slipped to fourth in the pecking order. He could “do a job”, just not the one for which he was needed.

Carragher never gave the impression that he enjoyed playing right back for England or Liverpool in any case, talking about how he felt uncomfortable exposed out on the flank and that was when he was younger and quicker. So why now does history appear to be repeating itself?

A simple rule for Capello is to pack his squad with as many specialists as he can, including the raw Leighton Baines as deputy for Ashley Cole rather than taking a punt that Milner can fill in at a push.

At right back, the test is to ask yourself who you would like to see there if Johnson was forced out through injury or suspension. Does Carragher feature in your top three?

A straw poll of half a dozen people in the game all concurred yesterday with the choice of Neville. Like me, they did not do so without reservation. Neville, 35, is vulnerable to pace now that the years are catching up with him.

But he played 11 of United’s last 16 games of the season, his worst injury problems seem consigned to the past and he is a full back with the ambition and scope not only to defend but to take the game to the opposition. He is, in short, a right back, not a right-footed defender. It is the job he has trained for every day for 20-odd years.

Neville can cross the halfway line without suffering a nose bleed and whip in a dangerous ball, which in Capello’s 4-4-2 formation is almost essential.

Out-of-position central defenders will not provide width.

Capello himself has talked for months about the need to take specialists rather than versatile cover. But now he finds himself wondering whether to contradict himself.

Whether Johnson will be able to play through the World Cup, and not suffer injury or loss of form, is slipping down his priority list behind his deep, justified concerns about his centre halves.

Rio Ferdinand is a back spasm waiting to happen while King has a dodgy knee. Capello is tempted to take a fifth centre back and now that he has lured Carragher out of retirement, he sees a way of getting away with it.

But to do so is to cause an imbalance that seems small now that we are a month before the tournament but that may yet come back to bite England just as it did with England in 2006, or 1998 when Glenn Hoddle took only one left-sided defender in Graeme Le Saux and ended up trying to squeeze the square peg of Gareth Southgate into the round hole on the left.

King must go as Ferdinand’s deputy, Milner as a marauding midfield player and Carragher as fourth-choice centre half (certainly ahead of Matthew Upson) but to expect them to fill in elsewhere is to start investing in hope above evidence.

Yes, they could “do a job” in other positions. But the day Capello relies on such versatility is the day he starts taking unquantifiable risks.