South Africa have called for an extra player to fly out with the rest of the squad to Sri Lanka on Monday as cover for the injured Herschelle Gibbs.

Opening batsman Gibbs twisted his ankle in a training camp at the Pretoria University High Performance Centre this week.

South Africa spokesman Gerald de Kock said on Friday that the United Cricket Board had agreed to add another player to the 14-man squad for the two Tests.

Two players -- debutant middle-order batsman J P Duminy and all-rounder Alan Dawson -- are due to join the squad on August 13 for the five limited-overs internationals. De Kock said the extra player will be named on Saturday.

South Africa coach Eric Simons said: "There is a degree of concern that Herschelle will not have recovered in time for the first Test and we have asked for a replacement, even though Gibbs will accompany us".

The South Africans arrive in Colombo on Monday and their first match is a three-day warm-up game against an invitation XI starting on July 30.

The first Test starts in Galle on August 4 and De Kock said there would not be enough time between the first two matches to fly over a replacement if Gibbs has not shaken off his injury.