Maria Sharapova has been out injured since August 2008
Former world number one Maria Sharapova has pulled out of next week's WTA Sony Ericsson Open in Miami.
The Russian, 21, who underwent surgery on her right shoulder last year, had hoped to play singles for the first time in Florida since August last year.
But she said: "I am still not ready to play seven consecutive matches and will have to withdraw from the Sony Ericsson Open, one of my favourite events."
Sharapova played doubles last week in the WTA Indian Wells tournament.
It marked her return to competitive action after missing the US Open and Beijing Olympics in 2008 as well as this year's Australian Open.
"It felt great to be back on tour last week even if it was just playing doubles," the three-time Grand Slam winner told her website.