Great Britain's hopes of qualifying for the Fed Cup World Group II have been hindered by the news that Heather Watson will miss the play-off tie against Argentina in Buenos Aries with glandular fever.
Watson was last week diagnosed with the virus after her first round defeat to Ayumi Morita in Miami and although doctors suggested the 20 year old was at the end of the fever, her recovery period is unknown.
And the Japan Open champion will be absent from the resumption of Britain's attempts to reach the World Group for the first time since 1993, with world No.39 Laura Robson leading a four-strong team to South America.
"I am very disappointed not to be able to play Fed Cup," Watson said. "I was really looking forward to getting back with the team and competing against Argentina.
"I will be following avidly and supporting the team from afar. It's a big miss for me and I will not only be missing the tennis but the team spirit and all the fun we have when we are together. I know the girls can win it and my thoughts will be with them."
Robson, the newly installed British No.1 will be joined by Johanna Konta, Anne Keothavong and Elena Baltacha, who returns after double-ankle surgery last year, with the quartet seeking to replicate GB's performance in Europe/Africa Group I in February where they qualified for the play-off phase alongside Poland.
"Of course we will miss having Heather with us in Buenos Aires but we are fortunate to have strength in depth and a great mix of youth and experience in our squad," said captain Judy Murray.
"This is a fantastic opportunity for GB to grab a place in World Group II and we will be doing everything we can to make that happen."
The British women will be hoping to replicate the heroics of the men's Davis Cup team, who reached September's World Group Play-Offs after a 3-2 win over Russia in Coventry at the weekend.
Britain have never previously won the Fed Cup but are four times runners-up, the last time coming in 1981, but possess the strongest female team for over a quarter of a century with Watson and Robson having become the first British female pair to be ranked inside the top fifty since 1987.