MEMPHIS, Tennessee -- American James Blake pulled out of the Memphis ATP/WTA tournament on Monday, complaining of a knee injury.
Blake was also forced to drop out of the tournament last year.
The second seed was due to face young American Donald Young in a first-round match on Tuesday.
After Blake's withdrawal lucky loser Sam Warburg came in to face Young.
Less than a week ago Blake lost the San Jose tournament final to 244th ranked Kei Nishikori of Japan.
It is the second successive year that Blake, 28, has pulled out of the event in which, in 2002, he reached his first ATP final.
Third seed Tommy Haas made a bright start by beating Diego Hartfield 6-3 6-2 in the opening round avenging a first round loss to the Argentine at Delray Beach earlier in the month.
A two-time defending champion and three-time overall winner of the hardcourt event, Haas, of Germany, took advantage of five service breaks to improve to 27-6 all-time in Memphis.
Last season, Haas successfully defended his title by beating top seed Andy Roddick 6-3 6-2.
Roddick is again ranked number one at the event and will start against Gilles Muller of Luxembourg.
The only other seed in action was number seven Jurgen Melzer of Austria, who battled past American John Isner, 6-7 6-3 7-6.
The only women's seed to play was number four Lindsay Davenport, who defeated German qualifier Sabine Lisicki 7-5 6-3 and next faces Russian Evgeniya Rodina, a 7-5 6-4 winner over Anastasiya Yakimova of Belarus.
Americans Vania King, Mashona Washington and Lilia Osterloh all lost.
The top seed is title holder Venus Williams, whose opening encounter pits her against 17-year-old qualifier Petra Kvitova of the Czech Republic.
Williams dropped only one set in the tournament last year and crushed Israel's Shahar Peer 6-1 6-1 in the final. E-mail to a friend