The Argentine, 30, has not played since hurting his right knee at Queen’s in June, during the build-up to Wimbledon.
Del Potro, who first fractured his kneecap last October at the Shanghai Masters, had surgery before returning home to begin his recovery.
“I’m very happy to tell you that I’ll play in Stockholm and Vienna in October,” he said on Twitter.
“These two tournaments are very special to me, as I had the chance to win both of them.”
He is a two-time winner of the Stockholm Open, which runs from 14-20 October, and also claimed the 2012 title in Vienna, where he plans to compete the week after.