Mannyball. What I think the Red Sox are thinking is similar to what Billy Beane tried to do when Jason Giambi left Oakland as a free agent after 2001. Moneyball gets into it on page 141:

"The A's front office realized right away, of course, that they couldn't replace Jason Giambi with another first baseman just like him. There wasn't another first baseman just like him and if there were they couldn't have afforded him and in any case that's not how they thought about the holes they had to fill. 'The important thing is not to recreate the individual,' Billy Beane would later say. 'The important thing is to recreate the aggregate.' He coudn't and wouldn't find another Jason Giambi; but he could find the pieces of Giambi he could least afford to be without, and buy them for a tiny fraction of the cost of Giambi himself."

Like replacing Giambi, replacing Manny would have little to do with foot speed and fielding ability. What Boston would have to replace is the OBP and SLG. Or, I suppose, improve the pitching staff to such a degree that the amount of offense needed to be replaced would be less. That could be done by getting 2-3 players with less-than-household names for less than $20 million. ... I still don't like this idea -- it's a huge gamble (signing any free agents is aways off; teams are forbidden to talk to anyone until mid-November) and I want Manny to stay in Boston -- but it does make a certain amount of sense from a financial standpoint.

And, from the main SoSH discussion:

12:43 pm: "Supposedly word out of [New York sports radio station] WFAN is that George has given the orders to claim Manny, stay tuned."