The Twins recalled right-hander Matt Garza from Triple-A Rochester and sent down catcher Chris Heintz.
Garza started for the Red Wings on Tuesday and gave up four earned runs over his five innings pitched. He'll join the Twins in Detroit on Friday and will be available to pitch.
Gardenhire, who said the decision to call up Garza was made by general manager Terry Ryan, said Garza would make a spot start in one of the doubleheader games that the Twins play in Chicago next Friday.
"Terry and the boys decided it was time," Gardenhire said. "He's been getting passed up by a lot of people, and it's time for the young man to come up here. Let's see where he's at throwing the baseball."
Garza has struck out 95 while walking just 31 batters and compiling a 4-6 record with a 3.62 ERA over 16 starts in Rochester, but he does not have much experience out of the bullpen, where Gardenhire had wanted an extra arm.
Garza, who many expected to make the Opening Day roster, expressed frustration earlier this season with how the Twins organization was using him.
"The feeling is, they want to see him in the big leagues," Gardenhire said. "He's getting a little frustrated so we're going to bring him up here and give him a chance to pitch for us," Gardenhire said.
Garza had been adamant earlier in the season about relying entirely on his fastball, while the organization wanted him to mix in other pitches. The disagreement led to several pitchers like Kevin Slowey and Scott Baker getting called up before Garza.
With the callup, Garza will get a chance to prove himself on the big-league mound, where he ultimately wants to stay.
"This is a good thing. He needs a little confidence boost, he's been fighting it. He wants to be up here with the guys."
Leslie Parker is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.