Who is he?
Soria is a 28 year old right-hander who didn't pitch in 2012 after undergoing Tommy John surgery in March. He spent the previous five seasons as the Royals' closer, saving 160 games in 315 1/3 career innings. He has a career 2.40 ERA, 2.90 FIP and 3.20 xFIP with an excellent 3.92 strikeout-to-walk ratio.
Why should we care?
Soria has put up some excellent numbers throughout his career, including two seasons with sub-1.80 ERAs. The fact that he has been worth 7.2 bWAR over the course of five seasons -- as a closer, mind you -- tells you just how dominant he has been. He was victimized by an elevated BABIP and home run rate in 2011, the only season he has ever had with an ERA over 2.50.
Why should we stay away?
I'm probably more wary of pitchers who have undergone Tommy John surgery than most, especially for relievers who rely heavily on going all out on every pitch. Soria might be healthy in time for Spring Training, but I'd expect him to be ready closer to May or June. There's also a good chance that someone offers Soria a multi-year contract, something that I would be a bit leery of when he hasn't pitched in a regular season game since 2011.
Will he end up in Detroit?
It's possible, but we likely will not see another free agent signing anytime soon. Soria would be an excellent upgrade for the back end of the bullpen if healthy, but I don't think he will be without a job for too much longer. There are a number of teams who have shown interest in him so far, including the Yankees, Red Sox, and Reds. I don't see the Tigers getting into a bidding war when they are so high on Bruce Rondon.