Hamilton is not a .600 OPS bat. That's Juan Castro territory.
He was .651 this year at AAA after a dismal slump, but was .830 in 2012 (A+, AA) and .700 at Dayton in 2011.
He has averaged an OBP of .350 in the minors (including this year's poor .308).
OBP is going to be key. I think he can do .350 or better. Heck, Ryan Freel did that for quite a while.