Walters, on the disabled list since June 14 with right shoulder inflammation, tossed three scoreless innings for Triple-A Rochester. He struck out six and walked two while throwing 59 pitches.
"He was fine," Twins assistant general manager Rob Antony said. "He felt good, everything's fine there."
Gibson, meanwhile, made his second rehab start with Class A Advanced Fort Myers. The right-hander, who is coming off Tommy John surgery last September, gave up just one run on three hits over four innings.
He's now pitched in nine games in the Minors this season, posting a 2.49 ERA with 23 strikeouts and five walks in 21 2/3 innings.
Right-hander Carl Pavano was scheduled to make a rehab start with Fort Myers on Tuesday, but will instead meet with Dr. David Altchek in New York. Pavano, on the disabled list since June 4 with right rotator cuff weakness, has been conferring with Altchek, but wanted to meet with him in person.
Antony, though, said that Pavano hasn't suffered a setback and that it was the only day Althcek could meet with Pavano. He's expected to make another rehab start in a few days.