Following his departure from NIU, Lute Olson hired Rosborough as an assistant coach at Arizona in April 1989, saying, “The thing with Roz is that he is a premier sideline assistant, as good as any in the business.” The Rosborough and Olson led Arizona Wildcats were a dominant and consistent collegiate basketball team through the 90's and 00's, reaching 18 consecutive NCAA tournaments, eight Pac-10 championships, three NCAA Final Fours, and the 1997 NCAA Championship.