The Johannesburg-based Highveld Lions expect the Durham paceman will join up with the squad next week and see him as an ideal short-term replacement for former Proteas international Garnett Kruger, who has been slapped with a ban for criticising so-called cliques in the national team.
"Obviously it could turn out nicely for us, in light of Garnett's banning," Lions bowling coach Gordon Parsons told The Star newspaper on Thursday.
"He was number one in the world at one stage, and if he is firing he will be handy for us.
"I hear he is quite a nice lad and it will be nice for me to work with him."
The 28-year-old, who has 205 Test wickets, last played for the national side in June during England's home series against the West Indies.
However he was ruled out of the following series against India as he underwent a hernia operation and a brief comeback was aborted when he suffered a muscle tear in his right lower back during a county championship match.
The spell in South Africa has been sanctioned by the England and Wales Cricket Board (ECB) as part of his rehabilitation process ahead of the three-Test series against Sri Lanka in December.
Harmison's experience will be badly needed by England after his fellow fast bowler Andrew Flintoff pulled out of the tour last week after undergoing keyhole surgery on his troublesome left ankle.