Mauer will catch games Sunday and Monday for Class A Fort Myers and possibly Tuesday. Then he'll bat against Joe Nathan on Wednesday and could be back in Minneapolis by Thursday.
Mauer will not play at Triple-A Rochester before being activated. Second baseman Tsuyoshi Nishioka is playing for the Red Wings on Sunday.
Gardenhire had said he wanted Mauer to play against Triple-A before coming up, just so he could see better pitching and fastballs.
"He can count on one hand how many fastballs he's seen since he's been playing down there, and that's kind of one of those reasons you might want to send him to Triple-A," Gardenhire told reporters, including John Shipley of the St. Paul Pioneer Press. "He might see some fastballs down there. There are some veteran guys who might know how to mix it up there. Those kids, they'll just be winging breaking balls all over the place."
Mauer's played in just nine games this season, going to the disabled list in April with what the team called "bilateral leg weakness."