At roughly 7:48 PM, it was announced via multiple Twitter posts that the Adrian Gonzalez trade had been completed.
The Red Sox will hold a press conference tomorrow (11 AM: a "major baseball announcement"), but it looks like there is no official contract extension. The prospects will remain the same.
SI's Jon Heyman posted that the team is "satisfied a multiyear deal can be arranged ... have common ground on parameters" and added: "Appears red sox will add about 7 yrs at about $23 mil per to a gon's $6 mil '11 salary. But no extension will be announced yet".
Which would be 7/161 (more or less) from 2012-18.
[UPDATE: Heyman's SI article states that "both sides have apparently agreed to the parameters of a new deal, believed to be for eight years and worth a total of about $167 million." That looks like Gonzalez's 2011 salary ($6.3) plus the 7/161 deal.]
Earlier today, Alex Speier of WEEI wrote:
...[I]n at least some respects, the best course the team can take might be to agree with Gonzalez to the parameters of a deal right now, and then wait until, say, April 8 (the day of the Fenway opener against the Yankees) to announce it. ...
The right shoulder, on which Gonzalez underwent surgery in October and that will keep him from playing until spring training, could serve as the ostensible justification to delay a deal. The Sox could say that they simply want to see the slugging first baseman back on the field and healthy before they formalize the extension. ...
The real reason why the Sox might want to wait until after the start of the regular season to announce an extension, if at all possible, is financial. Specifically, the luxury tax implications for the timing of the announcement of a long-term deal are huge.