Genealogy / SKI...SKY...ZKI...Polish surname endings [38]

Greetings all,
From what I know, my family is Polish, but anyone who knew /knows the details of our immigration to America is either dead or not willing to talk about it other than insisting that we are Polish, not Ukrainian or anything else. My family's current spelling for our last name is Rozyczko, which I'm aware is not a polish spelling, and past my great grandfather who immigrated with his wife, the name doesn't exist (and it's not the name he emigrated under, as there is no immigration record for that last name). Any ideas as to what the original polish last name could be?

Thanks for your help and time.