What a load of revisionist crap. Hansen absolutely dominated in his short professional debut in AA, albeit in a small sample, and they needed relief help in year they made the playoffs. It's as simple as that. A team makes that move 10 times out of 10. It didn't work out. Oh well.
As for the following year, I think the screw up is changing too many things with the way he pitches. He's still learning to do what they want him to. He's far from ruined. I mean, look no further than Cla Meredith, "ruined" after being called up. They got impatient, traded him, and now look at him in SD.