(Reuters) - With Rafa Nadal still out recovering from a knee complaint, David Ferrer will lead holders Spain in their Davis Cup semi-final at home to the United States, captain Alex Corretja said on Tuesday.

The world number five heads up a team that also includes Nicolas Almagro, ranked 12th in the world, Marcel Granollers and Marc Lopez.

"Ferrer is an example to follow," Corretja told a news conference.

"He said at the end of last year that he needed to rest, but he has reconsidered and when he has been needed, he has said yes."

World number three Nadal said on Monday he needed another two months off the courts to fully recover from a partial tear of the patella tendon and an inflammation of the Hoffa's fat pad in his left knee.

He has not competed since suffering a shock second-round defeat at Wimbledon in June, and has missed the Olympic Games and the U.S. Open.

"I want to thank Rafa Nadal for the effort he made to try and be with us," Corretja added.

"He tried but it wasn't to be, and I would like to pass on his commitment to the team. If he isn't here, it isn't because he did not try."

Spain, who are chasing a fourth title in five years, have the edge in recent encounters against the 32-time winners having won the last two times, though the countries are tied overall with five victories apiece.

The semi-final is to be played on clay in Gijon, northern Spain, from Sept 14-16.

(Reporting by Mark Elkington, editing by Pritha Sarkar)