Washington, Apr 23 (ANI): When Maria Sharapova underwent shoulder surgery five years ago, many thought her tennis career wouldn't last.

But now, there is a good chance the four-time grand slam winner will play into her 30s before fully turning her attention to her numerous business interests.

I think she's going to play another four to five years and through the Rio Olympics (in 2016) if she stays healthy and hungry, her long-time agent and close friend Max Eisenbud told CNN's Open Court.

Sharapova's motivation has never been an issue in the past, and the Russian-who turned 26 last week-is now fully fit.

That, however, wasn't the case in 2008, when the shoulder injury ruled her out for nine months and cast doubt on Sharapova's professional career, which began on the day she turned 14.

She had been experiencing discomfort in her right-and serving-shoulder, with initial tests leading doctors to believe inflammation was the cause.

When the pain intensified after a win at a tournament in Montreal in July 2008, she underwent an MRI that revealed two small tears in the tendon of her shoulder.

So began the long process of rehabilitation, surgery, another stint of rehab and dealing with another injury, a bone bruise. It was a difficult time for Sharapova.

She never lost faith that she would recover, but she would have to wait another three years before reaching another grand slam final, losing at Wimbledon in 2011.

Thankfully for Sharapova, no such serious injuries have reoccurred, although she was troubled by an ankle problem later that year.

I had to work through a lot of things, and more mentally as well because I always thought that during those months that I was away, everyone was working and everyone was training and everyone was playing so it kind of felt like I was left behind a little bit, she said.

Eisenbud's pronouncement about Sharapova's future comes as a boost to the women's tennis tour due to Sharapova's enormous star power and fan base, which increased when she won the French Open last June to cap her comeback and become just the 10th woman to capture all four majors. (ANI)