I like Marble and think he has a unique and useful skill set, but he is not nearly as good as Cully at the point at this time. The impact of losing Cully for the season will be revealed in BigTen play.
On the plus side, more minutes for younger guys and Cully has another year in the system to mature and learn the ins-and-outs of Frans offensive philosophy (note: I worked real hard there not to say "system").