I think if they don't resign Ray and renounce Green, they'll have more than the MLE to sign free agents. My dream scenario is replacing Ray, Bass, Steamer and Green with Jason Terry, Camby, Pietrus, Sullinger and Melo. The latter will have a more explosive second unit scorer and much better rebounding on both ends.
If the Celtics can add Camby and Sullinger in one offseason, they'll be a top 10 rebounding team on both ends next season. Their biggest weakness will become a big strength.