According to ESPN's Buster Olney, the Tigers are most definitely interested in trading for Diamondbacks pitcher Dan Haren.
Heard this: The D-Backs are in the process of exchanging names on Dan Haren. I don't know if any team is necessarily deeper into talks than other teams, but the Detroit Tigers are serious in their interest on Haren. Some execs have serious doubts about whether a Haren deal can be made, because the D-Backs will need a big-time haul in return for the All-Star pitcher.
For the Tigers, a "big-time haul" may mean trading away pitching prospect Jacob Turner as the centerpiece of a deal to land Haren. Also from Buster Olney:
Heard this: The Tigers are one of the teams involved in the Dan Haren trade talks, and some rival evaluators think that it would be very tough for Detroit to structure a suitable offer for Haren without including highly touted prospect Jacob Turner.
Baseball America ranks Turner as the 26th best prospect in baseball and the top prospect in the Tigers system. I'm not so sure if Haren would be worth giving Turner away, but it'll probably be tough to land him without including Turner. Quite a few teams are interested in Haren, so it's not like the Tigers can offer something small and hope that is enough. Chances are Arizona will get a few good offers, so the Tigers may have to give up a lot to emerge as the favorite to land him.