Miguel Sulbaran is a legitimate prospect. He's not a great prospect -- I don't think he'll be cracking any top 20 prospect lists this winter -- but he's a left-handed pitcher, age 19, having a good season in low A ball. That's a decent return for a weak-hitting defensive specialist catcher who was unlikely to remain on Twins 40-man roster this offseason.
The drawback on Sulbaran is his size, or lack of it. He's listed at 5-foot-10, 185, and that's small for a pitcher.
But he has a good arm. From John Sickels' "Baseball Prospect Book 2013":
Sulbaran now changes teams in the Midwest League, going from the Dodgers affiliate in Midland, Mich. (Great Lakes Loons) to Cedar Rapids.
...has performed quite well at the lower levels of the farm system, showing a 90 MPH fastball along with an effective curveball and slider. He trains with Pedro and Ramon Martinez and is said to have a good sense for his craft despite his young age...
No guarantees on Sulbaran, obviously. He's young, he's small, and he's a long way from the majors. But there's stuff there to like. Whether he makes it to the majors or not, this was a good trade for the Twins.