The Yankees are considering including a "non-disparagement clause" in future player and managerial contracts in order to prevent any more tell-all books such as "The Yankee Years," co-written by Joe Torre and Tom Verducci. Speaking on the condition of anonymity, a Yankee official said Wednesday that some members of the front office staff already are required to sign a confidentiality agreement in order to protect "proprietary knowledge of our business model." The proposed clause is intended to ensure that future books about the Yankees are "positive in tone," and "do not breach the sanctity of our clubhouse."