"The doctor is happy with the progress," he said on his Twitter account. "Now we have to keep strengthening [it] and then be ready for the racquet."
Shortly after undergoing wrist surgery in May, del Potro said he would not be able to defend his U.S. Open title and speculated he might not return till November.
Now, he says he may return in time for Argentina's Davis Cup semifinal against France. The tie takes place the week after the U.S. Open, suggesting that del Potro may be able to play at Flushing Meadows after all.
"Davis Cup is a good date for returning to the tour, I hope I can come back sooner," del Potro told Argentine press earlier this week. "I don't want to have any illusions because I don't know when I can return to [playing with the] racquet. But I'll train hard to prepare."