Gorzelanny has been sidelined since having surgery to repair tears to the rotator cuff and labrum in his left shoulder in early December. He began a 30-day rehab assignment at Class A Brevard County on May 14 before moving up to Triple-A the following week.
Though manager Ron Roenicke had been concerned about Gorzelanny's velocity in recent weeks, he said reports from the last few appearances in Nashville were more encouraging.
"No complaints. Velocity was up two outings ago, it was up really well," Roenicke said. "The command has been good, the slider's good. Obviously, we're hoping to see the same thing."
Gorzelanny made 10 appearances in the Minors, accumulating a 1.15 ERA, 12 strikeouts and two walks over 15 2/3 innings.
His activation will make for four left-handed options in the bullpen. Roenicke would like to ease Gorzelanny in but knows that might not be an option during this weekend's series against the Reds.
"He'll be in there as needed," Roenicke said. "It's usually [Joey] Votto-[Brandon] Phillips-[Jay] Bruce [for Cincinnati], and with that combination there, that's a good time to put him in. When he's throwing right, like he was last year -- especially when we had him in relief last year -- he pitched against anybody. It didn't matter."
Gorzelanny had a 3.90 ERA in 43 appearances (10 starts) with Milwaukee last season. He struck out 83 and walked 31 in 85 1/3 innings.
The combination of roster moves meant a surprising demotion for Schafer, who has not played regularly in the Minors since 2012. Schafer delivered a pinch-hit single in Friday's 6-5 loss to the Reds but entered the day with a .179 batting average in irregular duty.
"We're going with one extra guy in the bullpen and a four-man bench, so we'll try this for a little bit," Roenicke said. "Schafer needs to go down and get some at-bats and get his swing back. That's our idea."
Caitlin Swieca is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.