2015 rotation with Garza:
Obviously the 2015 rotation wouldn't include six guys, but having six legitimate arms potentially in the rotation is pretty nice. This also assumes the Twins don't upgrade between now and then. Trevor May could still take a step forward too. I really think that the 2015 season is the reason to sign Garza right now. Unless the Twins are very confident that they can get an equally impressive arm next off-season, they should just get a good starter like Garza while they can.
I only see Homer Bailey, Clayton Kershaw and Max Scherzer as true 2015 free agents who I prefer to Garza. I don't think Scherzer and Kershaw make it to free agency, meaning Bailey is the premier arm next off-season. I think the World of Bailey, but he's going to get paid. There are some guys with options for 2015 who might become available, but Johnny Cueto is the only guy I put in Garza's class. This is the best opportunity for the Twins to land a borderline number 2 starter without trading prospects.
I also think that signing another starter right now is great Hughes insurance, just in case Yankee Stadium wasn't the sole reason for his unimpressive stats. He's proven himself as a late-inning reliever and if he can't start, he might become an expensive set-up man or even closer. That's not ideal, but the Angels paid Joe Smith $15.75 mil over three years, so it's not completely off market value. If Hughes flames out, it would be great to have two starters who we knew would be better than him.