If you don't think the Twins should sign a Liriano-type to round out the rotation, what do you suggest they do?
Throw our own batch of bad arms out there that don't cost us 3-5 million. Hendricks, DeVries, a worthwhile FA, Diamond, Gibson, Deduno, etc. If you're going to willingly put bad pitchers in your rotation, why pay them a lot?
And I'm not against that move... If the Twins can pick up two legitimate starters. I'd go for a Sanchez/Jackson/Marcum type for 3 years and then sign Baker (pending physical and rehab status, that is). If you are confident that Baker can perform, snatch him up and fill in two rotation spots with filler until Gibson is ready (which he shouldn't be in April... If you start him out of ST, then you just have to bench him in August anyway... Better to do it the other way around).
But if Baker isn't ready or if another team picks him up, you can't expect the Twins to fill in three rotation spots with junk arms. That's a great way to start another season at 10-25 and be out of it by May 15th. In that situation, I'm not against picking up Liriano if he can be had for $3-4m. There simply aren't better options than him out there with the kind of upside he brings to the table. Just 24 months ago, the guy was getting Cy Young votes and it's not as if he suffered a major injury. He still has that kind of talent, though he's unlikely to pitch at quite that high a level again.
It's a bad situation to be in but advocating that the Twins throw out Deduno/De Vries/Walters/etc. is writing off the season before it even starts. There is absolutely no way the Twins will compete with three of those guys in the rotation.