Juan Martin del Potro says he is committed to returning from a left wrist injury that has required three surgeries. The former U.S. Open champion indicated that he has resumed some training, though he did not give a date for returning to tour.

Writing on Facebook, del Potro said, "The hardest moments of my career are gone, those in which I didn't know what I would do next. I've already told you the discomfort of being unable to do what I like and the suffering of watching tennis on TV. Today is a different story. I have great expectations for a new stage that began this week."

Del Potro pointed to his third surgery as a demonstration of his commitment to returning, explaining that the procedure was done largely to give him the ability to hit a two-handed backhand once again, and potentially get back to his previous level.

"Today I am more committed than ever to trying to come back," the Argentine said. "No more doubts or question marks. A new career for me starts today."

The 26-year-old has also previously had surgery on his right wrist. "Maybe I found more stumbling blocks than others did, but you have to jump over them," he said. "Three surgeries on my left wrist, one on my right wrist. I don't know how many cases like mine there were in tennis. I just know that when I have a goal I try to achieve it."

Del Potro will have to rebuild his team before returning, having announced this week that he is no longer working with his longtime coach, Franco Davin, and his trainer, who was also sidelined during his long layoff.

On his training, del Potro said, "This week I began rehab and did some light workout. While I start from scratch, I've been on a diet to maintain weight. I'll take the time that's necessary to name my new technical team."

Del Potro is currently ranked No. 570.