Caddick is still ranked among the world's best Test bowlers

He was hoping to make a comeback in the forthcoming Test series against South Africa after a stress fracture in his right foot put him out of the recent two-match series against Zimbabwe.

But it is believed that wearing an air-cast to support his foot may have aggravated an old back problem which has affected him on and off for the past two years.

He has been suffering from sciatica and underwent a scan last week, which revealed a prolapsed disc.

"Andrew has been given stronger medication to relieve the back problem," said England and Wales Cricket Board chief medical officer Dr Peter Gregory.

CADDICK'S ENGLAND RECORD 62 Tests, 234 wickets, average 29.91, best bowling 7-46 54 ODIs, 69 wickets, average 28.47, best bowling 4-19 Caddick's future uncertain

"If this does not control the pain, the specialist will give him an epidural injection in the near future.

"His condition will be reviewed by the specialist six weeks from now and if he has not improved, then surgery will be considered as an option.

"He will not play cricket during this time and has been advised by the specialist that he should rest for the remainder of the season."

New Zealand-born Caddick made his Test debut 10 years ago and has taken 234 wickets in 62 appearances at an average of 29.

The 34-year-old retired from one-day international cricket following the World Cup earlier this year in the hope of prolonging his Test career.

But he has been able to play only one County Championship match and a single one-day game for Somerset since the start of the summer.

He will want to challenge the younger guys and play for England again David Graveney

Chairman of selectors David Graveney described Caddick's latest injury as "sad news".

He said: "It's not going to be easy for him coming back after a whole season out and it will take a lot of hard work and determination, but I'm sure he won't want to finish in this way."

Regular new ball partner Darren Gough, who recently returned to the one-day team following three knee operations, has sent Caddick a message of support.

"He's a fighter, he's a good lad and he's a great bowler and I hope he gets back because he's a pleasure to watch when he bowls," said Gough.