If you want to know what I and the rest of my TYA colleagues think about who should/shouldn't be the 5th starter in this new rotation, head over there and check out this post. Pretty much every possibly scenario is covered.
If you haven't even started to consider who you'd like to see in that last rotation spot (Hughes, A.J. Freddy, someone else), this is a great way to read well-reasoned arguments for all 3 of the major contenders and form your own opinion.
Free Agent Updates: David Robertson
18 minutes ago