England have replaced injured paceman Ryan Sidebottom in their World Twenty20 squad with Dimitri Mascarenhas.
Mascarenhas bowled impressively in England's win at Lord's
Nottinghamshire's Sidebottom has not recovered fully from the side strain he suffered in the third Test with India.
Hampshire all-rounder Mascarenhas impressed in England's one-day series win over India and will join the squad in flying to South Africa on Sunday.
Meanwhile, Andrew Flintoff came through the final one-day match on Saturday but needed a cortisone injection to bowl.
The Lancashire all-rounder, who has been struggling with an injury to his troublesome left ankle, looked in pain at various stages of the match.
Captain Paul Collingwood said: "I think he was a little bit sore, but he obviously got through his overs.
"We're just going to have to assess how bad it is.
"Freddie is always willing - but obviously from a captain's point of view, you don't want to make anything worse.
"All the time, you're asking if he's OK. Today he said he was fine."
Mascarenhas, hugely experienced in the county game, has put in a number of excellent showings for England in the series in his first season of international cricket.
"He's been putting in these great performances for Hampshire, and now obviously there's a groundswell of opinion to get him into the England side," Hampshire cricket manager Paul Terry told BBC Radio Solent.
"He's shown what he can do, he's got the opportunity and he's taken it.
"Now he's got another opportunity to go away with England and play abroad, and we'll see how he does doing that."
One change has already been made to England's squad - James Anderson replacing Ravi Bopara - and doubts remain over Chris Tremlett, as well as Flintoff.