system
Given the following post, respond as if you're commenting on Reddit:
human
Confused about professor's reaction to asking if he'll be my PhD supervisor...?

I'm in my first year of a Top 10 PhD program that doesn't assign advisors (just for context). Since arriving, pretty much the entire PhD community assumed I would be working with a certain professor (since our research interests are about 100% aligned and there's not a lot of choice in that particular area). In fact, he asked me to be involved in 2 different projects almost immediately. We get along personally and professionally, no problems at all. I wanted to take my time, however, and investigate my options for supervisors. In the end, I decided it's true--he is the best match. When I asked him, however, he seemed surprised--hesitant, even. His response to "are you willing to supervise my PhD" was more or less "maybe, I think so." He first asked me to talk to a few other professors in the Dept (which I explained I already did) and implied it was a little early for him to know if our research interests aligned (except we've been spit-balling ideas for months now). In the end, he said "yes" I could put his name down with admin (I'm the LAST first-year to get a supervisor!). Is this a normal reaction? Should I be worried that he'll bail on me after the first year exams? Or, is this just a typical way for professors to make sure students have really given it enough thought? What was your PhD advisor's reaction when you asked? And, has anybody switched advisors in their second year?
gpt
It could be his funding situation. Many times in rotational based programs the PI ends up picking up the tab for the new recruit. If his R01 didn't get renewed this year, he might feel like he's not in a financial position to take on a new student.