The current rumor is the Jamey Carroll has agreed to a two year contract with the Twins and the Twins intend to use him as their everyday shortstop. In the past Carroll has been a utility infielder who can play 2nd, 3rd and outfield, in addition to shortstop. In the past, he has been very durable although he is now in his late 30's. At $7 million for two years, he will be making about $1 million more than Tsuyoshi Nishioka over the next two years.
There are also some rumors that Terry Ryan, talking about the middle infield, suggested he wasn't necessarily through with the middle infield. Apparently, Ryan indicated that questions about Trevor Plouffe's defense make him more a candidate for an outfield spot or DH. Neither Hughes nor Nishioki demonstrated a lot of defense in the middle infield last year either, so it would make sense that the Twins would be looking for more depth there.
It seems very likely that the Twins will start the year with Carroll and Casilla as their double play combination with Casilla at second base. Nishioka will be given a chance to take one of those spots or end up a utility infielder. Carroll's ability to play third base also gives the Twins some flexibility with Valencia. In many ways, Carroll is a perfect fit for a team trying to make sure no one comes to spring training guaranteed a job.