Two-time French Open champion Maria Sharapova has pulled out of the year's second Grand Slam tournament because of her injured right shoulder.

Sharapova announced her withdrawal on Instagram on Tuesday.

She wrote: ''Sometimes the right decisions aren't always the easiest ones.''

Sharapova said she has returned to practice and is ''slowly building the strength back'' in her shoulder.

The former No. 1 and owner of five major titles hasn't competed anywhere since late January, when she withdrew from a tournament in Russia after winning her opening match there. In February, she said she had a ''small procedure'' on her shoulder, which was painful since last year because of a fraying tendon and small labrum tear.

The French Open begins May 26 in Paris.