Maria Sharapova's arm injury that curtailed her WTA Tour return at the Bank of the West Classic has forced her withdrawal from next week's Rogers Cup.
The Russian made a comeback from an eight-week absence with a leg problem to win her first-round encounter with Jennifer Brady in Stanford on Monday.
However, Sharapova pulled out ahead of her scheduled round-two clash with Lesia Tsurenko due to pain in her left forearm, which will also prevent her participation in Toronto at the Rogers Cup.
A Sharapova statement, released by Tennis Canada, read: "I am so sorry to be missing Rogers Cup this year.
"I am so appreciative to the tournament for the wildcard and my fans in Toronto for their support.
"I am disappointed that injury is keeping me from the tennis court once again, and I will work as hard as I can to return to the game I love as soon as possible."
Sharapova returned from a 15-month doping ban in April, but skipped the entire grass-court season due to injury.
The five-time grand slam winner is still scheduled to compete at the Western and Southern Open in Cincinnati this month, but will have to go through qualifying to play the US Open if she does not receive a wildcard.