Butera was sent to AAA today along with Hollimon. This all but ends the competition for bench spots, unless the Twins go outside the organization for a utility infielder. Dinkelman and Towles are still in the major league camp, but its not likely either one will make the team. The Twins reportedly told Butera they were going with two catchers.
This almost certainly means that Morneau is going to start the year as DH, leaving Doumit playing in the field where he will still be available to backup Mauer. With Morneau at DH, Mauer will also likely have to play some first base and/or outfield if they want to keep his bat in the lineup on days he doesn't catch. So the roster looks like this:
Revere cf, rf, lf
Hughes 2b, 1b, 3b
Burroughs 3b, 1b
Plouffe was supposed to be moved to the outfield, but he is at second base in today's game. So it looks like they may be looking to have him play some infield. I said above that Dinkelman had no chance of making the roster, but Gardy could still surprise us by keeping him as the fourth outfielder/infielder instead of Burroughs or Revere. That seems very doubtful though. The more likely upset of the apple cart would be a legitimate shortstop from outside the organization to use as a utility infielder.
Update: I forgot to mention Brian Dozier. A decision to install him as the regular at shortstop would be another option. I don't think that is likely, but it would leave Carroll and Casilla to share second base and the utility role.