For instance:
BOS trades Lee to Memphis, who uses a TE to absorb Lee's salary
Memphis trades a 2nd rounder to Milwaukee
Milwaukee trades Sam Dalembert to Boston (Boston also sends out Jason Collins to the Bucks to make the salaries work)
Bucks turn an expiring contract into a TE of about $6 mil, cashable any time within a calendar year, plus a high 2nd.
Note: not going to argue for or against the above trade, just providing an example.