I'm a fourth year undergraduate philosophy student.
Last academic-year, I took a seminar with a professor that I had known reasonably well before I took the course. During that seminar we had several lengthy after-class conversations about a topic related to the seminar. The professor seemed to enjoy the conversations, and I think we developed a good relationship (as far as undergraduate student-professor relationships go).
I plan to write an essay and submit it to an undergraduate journal in December. I know that the topic of the essay is interesting to the professor and covers some unconsidered possibilities that the professor expressed interest in during our conversations. That is to say, I think he'd enjoy thinking about what I plan to write about.
This professor is the only one in our department knowledgeable about the subject, so I can't ask anyone else for their thoughts on the essay. Unfortunately, he's on sabbatical this year.
Would it be rude to email the professor in order to ask him whether I might discuss my argument with him a few times during this term?