Injury-stricken Rafael Nadal and Wimbledon finalist Andy Roddick will be among the big names forced to miss the Davis Cup World Group quarter-finals starting on Friday.
Nadal, who has lost his French Open and Wimbledon titles and his number one ranking to Roger Federer in the past month, is unable to turn out for champions Spain against Germany in Marbella due to his ailing knees.
Spain are also without David Ferrer, who has a muscle strain and has been replaced by former world number one Juan Carlos Ferrero, while a hip injury has forced Roddick's withdrawal from the U.S. squad to face Croatia in Porec.
The timing of the last-eight clashes immediately after the gruelling clay and grass court seasons again highlights the difficulties the players face with a packed calendar.
The Spanish, with Fernando Verdasco, Tommy Robredo and Feliciano Lopez in the squad, should nonetheless still be too strong for Germany on their favoured clay surface.
"We don't fear the Germans but we respect them a great deal," Spain captain Albert Costa told a news conference in Marbella on Tuesday.
Mardy Fish has been called up to replace Roddick as the United States bid to defeat Croatia for the first time, having lost to them in the first round in 2003 and 2005.
"Andy had a great run at Wimbledon. Understandably, his body is not up for the rigours of Davis Cup in such a short turnaround," U.S. captain Patrick McEnroe told the U.S. Tennis Association website (www.usta.com).
In Ostrava, the Czech Republic will be battling to reach their first Davis Cup semi-finals since 1996 when they host last year's runners-up Argentina.
It is not yet clear whether Radek Stepanek, who has a knee problem, will be fully fit.
Argentina, who beat the Czechs 5-0 in their last encounter in 2005, will be led by world number five Juan Martin Del Potro in the absence of the injured David Nalbandian.
The Israel-Russia tie in Tel Aviv is expected to attract the largest-ever attendance for a Davis Cup match in the country but the hosts appear to have given away a big advantage by moving it indoors from their regular outdoor home venue.
The Israeli Tennis Association said it expected a capacity crowd at the 11,000-seater arena, which is more than twice the size of the usual venue that is swamped by heat and high humidity in summer.
The Russians, winners in 2002 and 2006, go into the tie with number 24 Igor Andreev leading the charge in the singles. The rest of the team is made up of Marat Safin, Mikhail Youzhny and Igor Kunitsyn, who replaces the injured Dmitry Tursunov.
Israel will be led by world number 33 Dudi Sela who recently reached the last 16 at Wimbledon.
