England have called Kent spinner James Tredwell into their Test squad due to Graeme Swann's lingering injury.
Swann has suffered from a side problem but is expected to feature in the first Test against South Africa on Wednesday.
"Graeme's injury is improving and we expect him to be available," confirmed team director Andy Flower.
"But with a further three matches to come after Centurion we have decided that we need a 'like for like' replacement on hand for Graeme should this be required later in the tour."
Uncapped Tredwell, 27, was first called up for the 2007-08 tour of New Zealand.
He was drafted into the England one-day party during the recent 2-1 success over the Proteas, when Swann's injury first occurred.
But leg-spinner Adil Rashid was preferred when it came to selection, meaning Tredwell's action was limited to displays with the England performance programme, who are also in South Africa.