BERNE (Reuters) - Roger Federer's Davis Cup future was again the subject of debate following Switzerland's 5-0 defeat by Kazakhstan and relegation to next year's Europe/African group.

The defeat drew attention to Federer's last-minute decision to pull out of the team, announced on Wednesday only 48 hours before the start of the tie in Astana, because he said he was tired after the U.S. Open.

"The door is still open for Federer but the team will not be unconditionally directed around him," Erik Keller, chairman of Swiss Tennis's Davis Cup committee, told Swiss media in Astana. "We will not allow professional organization to be shaken."

World number three Federer has played 37 Davis Cup rubbers and led Switzerland to the semi-finals in 2003.

From 2005 until last year, he has only represented his country in the playoff round which decides whether they stay in the World Group for the following season or are relegated.

(Reporting by Brian Homewood, Editing by Ed Osmond)