In an interview with El Mundo Deportivo, Spanish Davis Cup captain Albert Costa says he isn't worried about Rafael Nadal and David Ferrer having to make the quick turnaround from indoor hard courts to clay for the Davis Cup final (December 2-4, in Seville), but he is concerned that they might get hurt during the upcoming ATP World Tour Finals.

"What worries me is that they might not be well physically, not the adaptation [to surface]," Costa said.

Costa also expressed confidence in his doubles team of Feliciano Lopez and Fernando Verdasco, but is unclear on which duo the Argentines will use. Juan Martin del Potro and David Nalbandian are expected to play singles for Argentina.

"They will come with five players," Costa said. "Del Potro and Nalbandian are the strong base, but do not rule out that Nalbandian may not play the first day [in singles]. And the doubles may be [Juan] Monaco, [Juan Ignacio] Chela, or [Eduardo] Schwank."

Costa also cautioned that while neither Nadal nor Ferrer has ever lost a singles match at home (Nadal is 18-1 in Davis Cup singles overall, and hasn’t lost a singles match since his first one in 2004) that Argentina could present a huge challenge

"Del Potro is getting his level back before his wrist injury, and next year will be back on top," Costa said. "And Nalbandian has been injured, but we know that he’ll be ready for Seville. He’s a super talent who has not won a regular basis because of  physical problems. But in a particular week he can play great. They are very dangerous, balanced and tough."