Maria Sharapova has withdrawn from March's Miami Open after having a "small procedure" on her shoulder. The five-time Grand Slam champion, 31, has struggled with an injury to her right shoulder since last summer. She previously withdrew from January's St. Petersburg Ladies' Trophy and next month's BNP Paribas Open in Indian Wells, California. "I am incredibly committed to getting back strong," said Sharapova in a "little update" on Instagram. "More importantly, without the pain I was playing with at the beginning of this year."