US Open champion Novak Djokovic is yet to decide if he will play for Serbia in the Davis Cup semifinals against Argentina.
The top-ranked player was expected to arrive in Belgrade later Wednesday or midday Thursday, said Serbia team captain Bogdan Obradovic.
The tie begins on Friday with two singles matches before the doubles on Saturday and another two singles on Sunday.
"He has two days to prepare and then we will see if he is going to play," Obradovic said. "Novak is used to this, he is a professional."
Djokovic beat Rafael Nadal in four sets on Monday in the US Open final for his third Grand Slam title this year. He also won the Australian Open and Wimbledon, but lost in the French Open semifinals.
The Serb has a 64-2 record in 2011. He led Serbia's Davis Cup team to its first ever triumph in the competition last year, and Obradovic said Djokovic's latest successes "give us this huge energy."
But he insisted that his team, which also includes No. 13-ranked Janko Tipsarevic and No. 16 Viktor Troicki, as well as doubles veteran Nenad Zimonjic, can manage without its star player.
"They can't wait to get out there," Obradovic said. "We are facing a great team."
Argentina are led by No. 17-ranked Juan Martin del Potro and David Nalbandian. Juan Monaco and Juan Ignacio Chela make up the rest of the squad.
Tipsarevic noted that "the Argentinian team is much better than their ranking."
"It is going to be extremely tough," said Tipsarevic, who retired from a US Open quarterfinal match against Djokovic because of an injury. He says he is now fully recovered.
Serbia made it to the Davis Cup semifinals after beating Sweden, while Argentina beat Kazakhstan.