Gagne, who received treatments on Sunday and said he feels good, threw a bullpen session at the Metrodome on Saturday.
"It's just good to get back on the mound," Gagne said.
DiFelice had a 3.95 ERA in 10 appearances with the Brewers. The 31-year-old will start games in the Minor Leagues, according to Brewers manager Ned Yost.
"He needs to continue to work on his ability to get left-handers out," Yost said.
Thor Nystrom is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.