Somerset have confirmed that Alviro Petersen will be available for this summer's Friends Life t20 competition.
The South Africa batsman was originally scheduled to play the first half of the season and leave Taunton before the domestic Twenty20 tournament starts on 26 June.
But the 32-year-old, who scored 106 in the innings victory over New Zealand in the opening Test in Cape Town last week, has now agreed to remain with the county until the end of July.
Petersen said: "I am very pleased that I will now be able to stay on at Somerset and play for them in the Twenty20 competition.
"Over the years they have done well in the competition and I would like to think that my contributions will help them to lift the trophy."
Somerset head coach Andy Hurry added: "This is great news for Somerset and having a top class performer like Alviro in our T20 squad will certainly boost our batting and bring a wealth of experience to the side."