According to a tweet from Jon Heyman, the trade that would have sent Adrian Gonzalez to the Red Sox has fallen through as the Sox and Gonzalez could not agree to a contract extension. While there's no other confirmation yet, if this is true, Red Sox Nation is going to erupt.

UPDATE: Ken Rosenthal concurs.

After the Padres and Red Sox agreed to the trade yesterday, the Sox were given a window of just over a day to sign Adrian Gonzalez to an extension before they would have to either annul or finalize the trade. The deadline passed with no announcement, and now nearly an hour later, it appears that the Sox just could not get it done.

There is a possibility that the Red Sox will choose to keep the trade anyways and continue negotiating, that would put the team's back up against the wall, forcing them to either agree to Gonzalez' contract demands or risk walking away from a deal that saw them trade two of their top-3 prospects for just one year of Gonzalez. For what it's worth, Dan Hayes hears that Gonzalez will not discuss an extension later.

If the deal has in fact fallen through, it's likely a matter of years more than dollars. Gonzalez was said to have wanted eight, while the Red Sox preferred six. The Sox have been burned in years past by deals with older players, which could explain their reluctance to sign Gonzalez into his late 30's.

More as it comes.