That's the problem, Freese seems to have fallen into the 3rd spot because everyone else fits their spots so well. Problem is that even once Kang comes back he's a pretty lousy fit for the 3rd spot as well. I guess at that point you bump Marte up and bat Kang 4th.
Right now I'd swap Polanco and Freese. Polanco is down in the line-up because he doesn't draw walks, and he has 9 already this year. Even without drawing walks his OBP was almost identical to Freese's last year, though...his bat is simply better.
I'd give thought to Cervelli, as well. He may be the weakest hitting #3 hitter I'd have ever seen, but he's posted a .370 OBP in consecutive seasons and has a knack for finding gaps. Really the only problem with batting Cervelli there is that it requires a separate line-up for when Stewart plays and I think Hurdle likes having his players bat in consistent spots.
I'm 100% happy with Jaso & McCutchen batting where they are. Jaso's career numbers batting 1st are rather absurd and anything that gets Cutch extra at bats is good with me.