My quick projected opening day roster/batting order:
1 Hicks CF
2 Mauer C
3 Willingham LF
4 Morneau 1B
5 Doumit DH
6 Plouffe 3B
7 Parmalee RF (?)
8 Dozier 2B
9 Florimon SS (?)
P - Worley
Not sure about the guys with the (?) next to them but it's my best guess. Mastroianni might get the starting CF spot out of spring training but, barring setbacks, it's a pretty sure thing that Aaron Hicks and Oswaldo Arcia will be in the majors at some point this season. They wouldn't have traded away Span and Revere if that wasn't the case. The middle infield remains a concern: Dozier slides over to 2B after a miserable performance at SS last year (I think he lead the league in errors at one point) and now Florimon gets a crack at SS (and I think the issue with him is his bat, not glove). I guess Carroll could be SS but at 40 years old I think he's going to be used more as a utility man. So frustrating that they've struggled for years now to find the right players for these positions.
Diamond would have probably been the opening day starter but now has a setback from some elbow cleanup work he had done. So that means the newly-acquired Worley is the best pitcher on the roster and becomes the "ace" by default. He's no scrub, he had a pretty good rookie season for the Phillies a couple years ago, but he regressed last year and is also coming off some elbow or shoulder issues. Let's take a look at this starting rotation:
Worley
Diamond
Correia
De Vries (?)
Hendricks (?)
Pelfry (?)
....?

The argument could be made that the Twins still have one of the worst starting rotations in the entire league, if not THE worst. Things don't start looking better until next year when Kyle Gibson, Alex Meyer, and Trevor May should all be up and hopefully bump Worley and Diamond down into the #3-5 spots where they probably belong. Gibson will get called up this year and should be good but I don't think he has ace-type stuff (projects to a middle-of-the-rotation guy at best). Alex Meyer, the guy they got from the Nats in the Span trade, could potentially be the future ace of the staff. He's a big 6'9" right hander with overpowering stuff but the earliest we'll see him is next year. The future of the pitching staff looks a lot better than it did at this time last year, but we're still several years away from anything resembling a playoff-caliber rotation.
I don't think they'll get close to 100 losses again but I just can't see this team ending above .500. The offense isn't terrible and has potential to put runs on the board but the pitching staff leaves a lot to be desired and overall they look like the weakest team in the division. Even if the Tigers falter or get hit by the injury bug I can't see the Twins being the team that takes control of the division.