As with Mauer and Capps, I think many are way too quick to write off Nishioka before seeing him play for an extended period. Virtually every former NPB position player has gone through a significant transition period, and with the injury issues last year, Nishi still hasn't seen extended play. With that said, I think a half-season at Rochester to show what he can do makes a lot more sense than giving him a half-season at Target Field to prove he can't.
Also, let's be careful about assuming Dozier is the middle-infield savior of this team: scouting reports on him give him only passable grades at 2B, and indicate he doesn't have the range to play SS in the major leagues. Just because he's the closest middle infielder in the Twins organization doesn't mean he's actually MLB-ready, or that he ever will be.
With all that said, Carroll has proven himself to be a capable middle infielder, and paired with Casilla/Hughes at 2B could represent a solid upgrade from the mess we saw last year, for at least a half-season. In the meantime, let's let Nishi and Dozier show what they can - and can't - do at Rochester or New Britain, and supplement the roster with Florimon (for defense) or with Burroughs (as a back-up 3B and potential DH/PH).
