I agree with Cris E that Ryan is likely to "leave teh team intact for the most part." I doubt that Ryan will trade either Perkins or Burton, and why should he? Burton is relatively inexpensive, and Perkins just signed a deal that will keep him here--likely as next season's closer. I also agree with Cris that Baker might be offered a restructured deal: something like $5 million for next year (he's coming off major surgery) + a team and player option for the following year at $8 or $9 million. So, a 2013 rotation could have Diamond, Baker, + a free agent + any of the following: Gibson, Wimmers, Hendricks, Walters, Hermson, and players like Walters (plus there is always the Rule 5 draft).
The offense is very good (usually), and then after 2013 Morneau comes off the books (is that true for Blackburn as well?). Off the books after (or during) this season: Capps (likely to be traded), Pavano, and Liriano (likely).
As far as trades go, it is possible that Span and Capps and Doumit get traded, and I guess it is possible that Liriano gets traded. I doubt all four get traded, and I doubt any bigger names on the team (i.e., Morneau and Willingham) get traded.
A winning 2013 team is possible. The Twins got the offense going and the bull pen going, so far, this season, and you would expect them to be strong in these area next year. It is certainly conceivable that the Twins can have a stronger rotation next season. I don't think that they will start out 5 and 15 like this season.