The Celtis might be interested in either Monroe (for obvious reasons) or JSmith (because he seems to be a friend of Rajon). So why not trade one of the two (Monroe only if he forces a trade) and Brandon Jennings for the Boston Pick - assuming that the pick is Marcus Smart (that gives us a real PG) and Green (gives us a real SF) and Wallace (gives a financial flexibility next year).
Smart / Siva
KCP / Morrow (free agency)
Green / CJ Miles (free agency) / Singler
Monroe or Smith / Wallace / JJ / Mitchell
Drummond / Harrelson / Draft Pick