Federer had been expected to play in the $2.2 million Dubai Tennis Championships next week and in the Davis Cup first-round match in March for Switzerland against the United States but he said a back injury last fall hasn't completely healed.
"After injuring my back last fall, I did not have enough time to strengthen it completely," Federer said in a statement on his Web site. "As a precautionary measure, I will use the next few weeks to make sure the back injury is fully rehabilitated and I am ready for the rest of the 2009 season."
Federer hasn't played competitively since losing the Australian Open final to No. 1-ranked Rafael Nadal, who has also hinted that an injury may keep him out of the Dubai tournament.
Federer won the Dubai ATP stop four times and called the event "one of my favorites on tour" in announcing he his withdrawal.