With the Tigers announcement yesterday that Austin Jackson would indeed be the opening day center fielder, this doesn't come as a huge surprise. There is still one spot on the 25 man roster open and the odds on favorite appears to be Don Kelly.
Too bad, I like Thomas. He strikes out way too much, but posts respectable OBP numbers, plays solid defense at all three outfield positions, and can do some work on the base paths. Thomas will never be a star, but could make a decent career as a 4th outfielder.
That said, as utility players go, Kelly does provide fantastic flexibility with the ability to play pretty much everywhere. He's logged time at every position except for center field and catcher in his Major League career.
Offensively Kelly wont add much, I'd expect the same overall performance with the bat as Clete Thomas, though with fewer strikeouts.