The Twins haven't made it official, but after sending Ramon Ortiz to the bullpen Sunday, they plan to promote Kevin Slowey from Class AAA Rochester to pitch Friday's game at Oakland.
Manager Ron Gardenhire said the new pitcher will join the team before it leaves for the West Coast on Thursday.
Slowey leads the International League with a 1.54 ERA. He is 6-2 and has 57 strikeouts, with just five walks. He's not on the 40-man roster, but the Twins can clear a spot by placing Jesse Crain on the 60-day DL.
Slowey will become the third Rochester starter -- joining Glen Perkins and Scott Baker -- to leapfrog top pitching prospect Matt Garza to the majors this year.
Garza is 2-5 with a 3.21 ERA for Rochester, with 53 strikeouts and 22 walks. Last week, in an interview with the Pioneer Press, Garza criticized the Twins at length for urging him to throw more off-speed pitches.
"It's immaturity and frustration," Twins pitching coach Rick Anderson said. "Terry Ryan and Jim Rantz were just there watching him, and instead of telling them, he tells the media. He'll get it over it. Maybe he needed to vent."
Ortiz posted a 10.97 ERA in five May starts, but the Twins have a legitimate need in their bullpen after losing three relievers to recent injury.
"He said, 'Anything you want me to do, I'll do,' " Gardenhire said. "He handled it very well, like I thought he would. Like a good teammate."
Mauer pushed back
Joe Mauer ran the bases Monday but continued to feel tightness in his strained left quadriceps muscle.
The Twins had hoped he would be ready to play vs. the White Sox, but with an open date Thursday, it's looking more like Friday.
"That could be a target date, barring a setback on the bases, but he feels really good," Gardenhire said. "He's working his tail off to get there. It's still there a little bit, and maybe as he stretches it out a little more, running harder and harder, he'll be past it all."
Luis Castillo is a natural righthanded hitter, but you'd never know it looking at his season splits.
The switch hitter is batting .384 from the left side, and .178 from the right side.
Castillo is a .302 career hitter from the right side, and .290 from the left side, so those numbers should eventually even out.
"I've been waiting," Castillo said. "I know it's coming."
White Sox manager Ozzie Guillen was Florida's third base coach when Castillo played for the Marlins, and Guillen was not surprised Castillo has set a new major league record for second basemen, going 137 games and counting without an error.