Montreal - Venus Williams is withdrawing from next week's WTA tournament in Montreal, citing an injured left knee that is hampering her preparation for the US Open.
The No. 4-ranked Williams already had pulled out of this week's hard-court event in Cincinnati, another warmup for the year's last Grand Slam tournament, which begins Aug. 30.
In a statement issued by the Montreal tournament, Williams says she's looking forward to playing there for the first time, "but the pain that I am experiencing in my knee has unfortunately not gone away."
The seven-time Grand Slam champion hasn't played a singles match on tour since June 29, when she was upset in the Wimbledon quarter-finals by 82nd-ranked Tsvetana Pironkova of Bulgaria.