GENEVA — Roger Federer, stuck in a slump, said he will work with coach Jose Higueras at the Estoril Open in Portugal this week.

"I am excited as I have asked Jose Higueras, one of the most respected and accomplished coaches in the world of tennis, to join me," the top-ranked player said on his Web site today. "We are going to spend the week together to see if we could make a good team."

Federer begins the European clay-court season at Estoril having failed to reach a final in four tournaments this year.

Higueras is a clay-court specialist who coached a teenage Michael Chang to the 1989 French Open title. The Spaniard reached two semifinals at Roland Garros as a player and also has coached Americans Jim Courier, Pete Sampras and Robby Ginepri.

"It is a test period, but it is not just something for the clay-court season," Federer's agent, Tony Godsick, told The Associated Press. "Roger is not looking to hire coaches just for specific surfaces. This is something he is testing out to replace the arrangement he had with Tony Roche."

Federer has worked without a coach since splitting with Roche last May. He is off to his worst start to a season since 2000, due in part to a stomach virus and mononucleosis.

The 26-year-old Swiss star plays 80th-ranked Olivier Rochus of Belgium in the first round at Estoril tomorrow. Federer is scheduled to play Masters Series events on clay at Monte Carlo, Rome and Hamburg, Germany, before attempting to win his first French Open title.