SA's preparation for a limited-overs home series against England suffered a jolt with three players placed in isolation after one of them tested positive for the novel coronavirus.

Nearly 50 tests were conducted before players and support staff entered their bio-secure base in Cape Town for the series featuring three Twenty20 Internationals followed by an equal number of one-dayers.

"One player has returned a positive test result and two players were considered close contacts based on the risk assessment undertaken by the medical team," Cricket South Africa (CSA) said in a statement on Wednesday.

"All three players have been placed in immediate isolation in Cape Town as part of the Covid-19 protocols. While all players are asymptomatic, CSA's medical team will monitor them to ensure their health and well-being."

The three were not identified.

South Africa have not named any replacement but two new players will join the group for the inter-squad practice matches on Saturday.

The series, which will be played behind closed doors, gets underway with the first Twenty20 match in Cape Town on Nov. 27.