With Ledley King ruled out of Friday's game against Algeria with a groin strain, Fabio Capello must decide who should partner John Terry at the heart of the England defence.

From his Johannesburg base, Scott Wilson looks at the three candidates for the role and assesses their strengths and weaknesses

JAMIE CARRAGHER

Tackling: Widely acknowledged to be one of the most reliable tacklers in the Premier League, and comfortable making a challenge off either foot.

Particularly well suited to dealing with a forward playing in front of him, the only question mark relates to his ability to tackle an attacker running past him at pace. 8

Heading: Solid, if unspectacular. Generally holds his own in the air, but rarely dominates an opponent, especially if they boast a height advantage over him.

Has spent some of his career at full-back, where heading is not as important, and would probably rely on Terry attacking the majority of long balls. 5

Positional Play: Can occasionally be suspect. Earned a yellow card on Saturday after he was pulled too far up the field and was struggling to get back.

Is happy enough holding a solid line when the play is in front of him, but can sometimes leave gaps which can be exploited by a player emerging from the deep. 6

Pace: A major worry. At the age of 32, Carragher is not as fast as he used to be and there must be a fear that he will suffer against a nimble Algerian attack.

His lack of pace was clinically exposed on one occasion on Saturday, as Jozy Altidore surged past him before hitting the post. 3

Experience: Carragher's strongest suit. He won his 37th cap against the United States, and even though his England career included a three-year hiatus when he was effectively retired, he is tried and tested at international level.

He has also won a Champions League and a UEFA Cup with Liverpool, and appeared in FA Cup and Carling Cup finals. 9

Form: Not the best. Last month's international recall was especially surprising as it came at the end of a domestic campaign in which Carragher rarely performed at his peak.

Saturday's second-half display was the performance of a ring-rusty player and can have done little to bolster his confidence. 5

TOTAL: 36/60

MICHAEL DAWSON

Tackling: On his day, one of the best tacklers in the England squad. Generally times his challenges well and concedes far fewer fouls than he once did in his youth.

The only concern is an occasional tendency to leap in unnecessarily, a weakness that would almost certainly earn him a booking in a World Cup finals. 7

Heading: An area of his game that came on in leaps and bounds last season. In the past, Dawson tended to leave most of the heading to his central-defensive partner.

He wasn't able to do that last term, with King and Jonathan Woodgate injured, so he has learned to take much more aerial responsibility himself. 6

Positional Play: Normally pretty good. Doesn't get pulled out of position anything like as much as he used to and finished last season as the leader of the Spurs defence.

There is a slight concern about players running behind him, but slotting in alongside Terry shouldn't be a problem. 7

Pace: Probably the quickest of Capello's three options, but that isn't really saying a lot. Generally one-paced, which wasn't too much of an issue for Spurs given the presence of the lightning-quick Sebastien Bassong.

It would be more of an issue for England, and while he can hold his own over longer distances, he is susceptible to a burst of speed over a short distance. 5

Experience: Pretty much non-existent and, for that reason, it would be a major surprise if Capello handed him a starting spot on Friday.

Dawson is the only member of the England squad not to have made a single international appearance, although he has won a Carling Cup with Spurs. 2

Form: After a particularly successful season at club level, North Yorkshireman Dawson is in the footballing form of his life.

He will have travelled to South Africa full of confidence, and insists he is ready to do himself justice if called upon to face Algeria. 8

TOTAL: 35/60

MATTHEW UPSON

Tackling: Doesn't produce any frills, but normally gets the job done. Like the rest of England's defenders, is more comfortable dealing with attackers playing in front of him, but can adapt fairly well.

Doesn't pick up a lot of yellow or red cards, which suggests his timing is normally fairly reliable, and seems to know when to tackle and when to hold back. 7

Heading: Aerially, Upson is the strongest of England's three centre-half contenders. Normally assumes heading responsibilities for West Ham and is rarely out-jumped.

Perfectly comfortable attacking the first ball, and is also capable of posing a threat in the opposition box off corners and set-pieces. 8

Positional Play: On the upside, partnered Terry in a number of England's qualifiers and is used to playing alongside the Chelsea man and adapting his own positional play accordingly.

On the downside, was occasionally pulled out of position for West Ham last season and can leave gaps behind him for attackers to exploit. 6

Pace: Just about adequate. Isn't the quickest defender in the game and has found himself outpaced at both club and international level in the past.

However, tends to compensate by dropping a bit deeper, which should help him deal with an Algerian side that is rarely too adventurous. 5

Experience: A major positive, and one of the key reasons why Capello refused to axe him from the provisional squad.

Upson has won 19 senior caps and appeared in five of England's ten World Cup qualifiers. Up to this point, he has never let Capello down at international level. 8

Form: Has to be a concern given West Ham's struggles in the Premier League last season. Upson was widely regarded as one of the Hammers' better players, but that is surely a case of damning with faint praise.

The only West Ham player in the squad is Robert Green, and we all know what happened to him last weekend. 3

TOTAL: 37/60

VERDICT: Two things stand out immediately. First, only two marks separate all three players, confirming there is little to choose between them as Capello ponders his options for Friday night.

Second, none of the trio score more than 37 out of 60, underlining how much of a weakness the centre half position has become following the withdrawal of Rio Ferdinand and an injury to Ledley King.

Dawson boasts the best form of the trio, but pitching an uncapped player into a crucial World Cup group game would be a big call, and for that reason alone, Capello is unlikely to make it.

Carragher got the nod to replace King on Saturday, but his lack of pace was exposed early on and his performance dampened his claim for a starting spot, rather than enhancing it.

Therefore, despite reservations over his poor season with West Ham, Upson looks like being Capello's best option. He has produced for England in the past, and is capable of repeating the solid showings he turned in during qualifying.