Hansen underwent a procedure today which was meant to cure the sleep apnea. The sleep disorder has reportedly caused Hansen to be exhausted for during much of his activities throughout the day. Whether this will cause his control issues has yet to be seen, however.
Hansen's still got potential. He can throw the ball 98 mph, and has a slider gets up to about 88 mph. But at age 23, it will be hard to talk about Hansen's "potential" for many more years. If Hansen can't walk less than a better every other inning at the Triple-A level, he'll never have much of a future in the majors.