Somerset will be without opener Alviro Petersen for a month following his call-up to South Africa’s squad for their Test tour of Sri Lanka.
Petersen is joined in the 15-man squad by Surrey’s Hashim Amla - who will skipper his country for the first time in the two-Test series which begins on July 16 - and Kyle Abbott, who is at Hampshire.
Petersen is set to be away from Somerset from July 11 until August 14 – a timeframe that also includes the Proteas’ following series against Zimbabwe.
Somerset hope to sign a replacement player in the coming weeks.
“Having had such a good start to my season with Somerset of course I am very disappointed to be having to spend time away,” said Petersen, who has scored 517 championship runs at 57.44 this season.
“However, it is always an honour to be picked for my country and I look forward to returning to pick up my season back at the County Ground later in August."
Somerset director of cricket Dave Nosworthy said: "Congratulations to Alviro once again for being chosen to represent his country - I have no doubt that he will perform superbly.
“Naturally it is always tough to lose ones overseas professional - but these days such signings come with the territory.
“He will be away for just the five weeks and we will hopefully be announcing a replacement player shortly for this period."
Amla is also included in South Africa’s one-day squad for the three-match series against Sri Lanka, which begins on July 6.
The 31-year-old was drafted in by Surrey as a replacement for countryman Graeme Smith after he was ruled out for the rest of the season last month with a knee injury.
Amla was named as Smith’s replacement as Proteas Test skipper last week - following the left-hander's decision to call time on his international career - and will take the reins for the first time when the first Test begins against Sri Lanka in Galle.