My premise is that the Twins don't see Pinto as an everyday catcher (just a premise, not a fact); and of course there's risk in making a trade like this. I think the catching pipeline takes a big jump this year with Turner and Navarreto.
The Twins were in heavy on Salty so it's safe to say they have some lingering questions about Pinto.
And everyone better get used the idea of Suzuki as their everyday starting catcher...
the addition I would make to your premise is "yet". The Twins don't see Pinto as The a Everyday Catcher yet.
i think the interest in Saltalamachia reinforces the Butera rule that the Twins value depth at catcher, don't feel that Pinto is a sure thing yet, and they wanted insurance.
When TR didn't land Salty, he went with plan B, the cheap defensive veteran that won't clog the space for Pinto.
Look for Pinto to start in AAA, tear it up offensively and improve enough defensively to earn a promotion, and become the primary catcher with the big league club by June.
i don't see TR making the trade (even if they could) because of the value placed on depth at catcher.
I also wouldn't make the trade, because Pinto is your only decent hitting option he will bring in more runs in 2015 and on, than either of the two SS trade options.