Walters, who is eligible to come off the DL on Saturday, will throw another bullpen on Friday to get ready for Sunday's rehab outing.
"If all goes well, there's a good chance he'll throw Sunday down in Rochester and then we'll go from there," Twins manager Ron Gardenhire said. "We'll see how that works out."
Walters said his shoulder is feeling much better and that he didn't feel any discomfort in his throwing session on Tuesday.
"Everything was good," Walters said. "Everything seems headed in the right direction. I'm happy. There's no pain."
Walters, 27, posted a 5.40 ERA in seven starts before being placed on the DL on June 14 after allowing four runs without recording an out against the Phillies on June 13.