Johannesburg - South Africa's No 1 tennis player Kevin Anderson has been given a week-end deadline by team captain John-Laffnie de Jager to make himself available for the critical Davis Cup tie against Slovenia at the Arthur Ashe Tennis Centre in Soweto early next month.
The 30th world-ranked Anderson slumped to a fourth successive defeat against world No 1 Novak Djokovic at the Indian Wells Masters tournament on Monday.
His presence is considered paramount to ensure South Africa beating a well-balanced Slovenian combination.
"Anderson stands out in the rankings among the players from both South Africa and Slovenia and would swing the balance of power heavily in our favour if he makes himself available for the Soweto match," De Jager said.
The South African Davis Cup captain said that after reaching the World Group playoff stage for the past three years, but stumbling at the final hurdle, it would hopefully be a case of "fourth time lucky this year."
"I think we have the necessary components to make this happen," he said.
"But we need Kevin's input to feel confident of winning the Slovenia tie and then going forward to some pretty tough potential opposition in the World Group playoffs."
If Anderson does not play against Slovenia he will also sacrifice the chance of competing at the London Olympic Games tennis event which will take place at Wimbledon later this year.
The International Tennis Federation stipulates that only players who have competed in the Davis Cup for at least two of the past four years are eligible for the London showpiece.
While Anderson is concentrating on improving his world ranking and earning a prized place among the top 20 players in the world, it is thought the Olympic carrot might influence him to make himself available to play against the Slovenians.
So far, this has not happened and with the Slovenia tie little more than three weeks away, De Jager is noticeably uneasy.
De Jager has confirmed that all the country's other leading players are available for the coming Davis Cup match.
Ironically, while Anderson was exiting from the high-profile Indian Wells after his 6-2, 6-3 defeat against Djokovic, another South African-born player Matthew Ebden gained a shock 6-3, 6-4 third-round win over top United States player Mardy Fish.
Durban-born Ebden now resides in Australia and has made himself available for his adopted country.