Walters, who has been out since June 14 with right shoulder inflammation, tossed two perfect innings for the Red Wings. He threw 18 pitches, 11 of which were strikes.
Walters is expected to make a few more rehab starts, as he's on the 60-day disabled list.
"He felt good," Twins assistant general manager Rob Antony said. "We'll play it by ear; he's been out a long time, so it's going to depend on how he feels. We'll increase him, and when he's ready to go and resume normal activity, then we'll do something." Twins manager Ron Gardenhire said the club will decide what to do with Walters once he's healthy, as the rotation has been solid recently. In nine games dating back to July 27, Twins starters have a 2.20 ERA.
"Whatever presents itself, we'll figure it out," Gardenhire said. "I hope he gets better and I hope he gets well, but he's got a ways to go. He's still on the 60-day DL, so he still has a lot of time here. So we'll keep going with what we have, and once those things present themselves, we'll figure it out."