England have called Alex King and David Rees into their injury-hit squad to provide cover at out-half and on the wing for Saturday's international against South Africa at Twickenham.

But Matt Perry has been ruled out of the Test against the world champions with concussion which will keep the Bath full-back on the sidelines for a mandatory three weeks.

Northampton out-half Paul Grayson (knee) and Leicester centre Will Greenwood (groin) remain doubtful starters. Jonny Wilkinson and Kyran Bracken are out of contention because of knee and shoulder injuries. Coach Clive Woodward expected to name his line-up at Twickenham tomorrow.

England's troubles have been compounded by the surprise loss of Perry, one of their few creative players in a threadbare attack that mostly struggled during last Saturday's 12-11 defeat by Australia in their Cook Cup international.

If Grayson fails to pass muster, Mike Catt, who came on as a replacement last weekend, is likely to retain the number 10 shirt.

Woodward has a number of intriguing options to ponder over the full-back vacancy. The versatile Nick Beal, who has worn the number 15 shirt with distinction for Northampton, could be promoted from the bench to take Perry's place, having served as a Test centre on the summer tour.

Meanwhile, South African hooker James Dalton, who is rated doubtful for Saturday's Test, said he was still hopeful of playing in the Twickenham showdown.

"I am confident that my hamstring will have recovered by the weekend," he said.