According to MLB.com's transactions page, the Tigers have demoted left-handed reliever Daniel Schlereth to Triple-A Toledo to free up roster space for right-handed reliever Brayan Villarreal, who's being promoted from Toledo to bolster Detroit's bullpen.
Schlereth, Detroit's 2008 first-round pick, was supposed to be a fast-moving reliever that could quickly help the Tigers' bullpen, but he's just another example of a flame-throwing reliever taken in the first round that doesn't have the immediate impact that he's supposedly capable of. He's posted some big numbers in the minors, but has constantly struggled with his command and his fastball has averaged just 91 MPH this year, down from 93 MPH in 2009.
Villarreal isn't expected to a long-term piece of Detroit's plan, as the 24-year-old has been quite underwhelming as a starter with Toledo, but the Tigers appear to believe that Schlereth could use some time in the minors to work on his game. Detroit could also use a fresh arm considering how poorly Phil Coke has pitched of late.