The Yankees haven't made a final decision regarding Bernie Williams, a source told The Post yesterday afternoon. But that doesn't mean Williams will be back since there is little room for him on the 2007 roster as it currently stands. Williams' agent, Scott Boras, did not return phone calls yesterday, and GM Brian Cashman is on vacation this week. However, the source believed Cashman was still having dialogue with Boras and the Yankee GM may have even spoken with the 38-year-old Williams directly at some point this winter.