Emailing a postdoc offerer for future reference?

[Hercuflea]

Would it be acceptable to look at post-doc offers (as a pre-PhD student) and email the offerer to ask whether they would accept a PhD in X field? If a post-doc says it requires you to have a PhD in a "closely related field", would it be alright to email them and ask if you do a PhD in something if they would take that?

 

[e.bar.goum]

If it says "closely related field" that's what they mean. However, it's obviously not just a matter of how close your phd work is to the project, it's also the strength of your work and your manner.