Sports Ilustrated's Jon Heyman is reporting that the Detroit Tigers have acquired starter Doug Fister from the Seattle Mariners. 

The Tigers have acquired Mariners starter Doug Fister. The deal may include the Tigers' Charlie Furbush and Casper Wells and Mariners pitcher David Pauley.

Detroit had called up top pitching prospect Jacob Turner to start Saturday, but with this move Turner may be ticketed back to the minors after his debut.

CBSSports.com's Danny Knobler is also reporting that the Tigers are shipping third base prospect Francisco Martinez to the Mariners:

Tigers could trade Martinez because another top prospect, Nick Castellanos at A West Mich, is also a 3B. #tradedeadline

Despite compiling a 3.33 ERA, Fister win-loss record stands at 3-12 due to an incredible lack of run support from the Mariners offense in his starts. The Tigers will be receiving a more than capable third starter in Fister.