From ESPN:

The Yankees have changed their traditional stance and are now willing to negotiate during the season with their star third baseman on a contract extension, MLB sources told ESPN The Magazine's Buster Olney.

The article also notes that the sticking point for the Yankees is that A-Rod keep his current contract and work with them to add an extension to it. This is important because the Rangers are helping to pay for the rest of A-Rod's current contract.