Originally Posted by nononora
You can certainly phrase it in a way that doesn't convey the fact that they're not your top choice. Perhaps something along the lines of wanting to meet staff/faculty at other sites before deciding on what would be the best fit for personality, training goals, and interests?
I don't mind asking them to wait a little bit, but the majority of the sites I'm interested have deadlines in mid/late February and won't notify til mid-March and I feel like it would be unreasonable to ask the site to wait that long even if I explain it nicely. I'm sure I won't get interviews at all of the sites, but it could still be March before I find out from some of them if I'm getting an interview or not.