I just faced a funny, yet complicated situation!
I want to apply for postdoc positions, and one of my references would be a professor that I had a good collaboration with his group during my PhD. However, I ran into him a few days ago and informally asked if he has any available position in his lab. He said that he is too busy now but likes to sit together and talk about it 4 weeks from now! Although I liked the idea, it'd be too risky for me to wait that long until I see if our meeting could result in a position or not. So, I want to proceed with my position search meanwhile!
The issue is that I'm not sure how the professor would see it (or react) If anyone contacts him as one of my references for my postdoc applications! Even I am not sure how to tell him that want to add him to my reference list! In fact, I am afraid to lose the chance of working with him as well as his positive recommendation for my applications?
BTW, If it helps, the country is Germany, and the field is computer science!