Roger Federer will miss Switzerland's Davis Cup matches against the United States and next week's tournament in Dubai as he rehabs a back injury.

Federer said on his Web site today he did not have enough time to completely strengthen his back after hurting it last fall. He says he is taking a precautionary measure.

Switzerland faces the U.S. in the first round of the Davis Cup on March 6-8 in Birmingham, Ala.

Federer says Dubai is one of his favorite tournaments, and he regrets being unable to help his country in the Davis Cup. Federer is ranked No. 2. He lost to Rafael Nadal in five sets at the Australian Open final.