This seems like the type of move that a desperate baseball team would make, not a team that is leading the AL East with the 2nd best record in baseball. Clemens would be a fine acquisition but not for Hansen. Murphy yes, Hansen, no way.
Hansen is 3 years younger than Joe Nathan was when he started in the bigs for SF, and he is 4 years younger than Brad Lidge was when he first started with Houston.
When Mariano Rivera was Hansen's age he was still 4 seasons away from making it to the Yankees.
I know, those are lofty comparisons but they are simply to prove a point. Hansen has done a phenomenal job for someone who is 22 and still learning how to pitch. I wouldn't trade him for a 43 year old with 14 weeks left in him.
Interesting thought though.