I'm not saying I buy this, or that I even necessarily want Ortiz in a Yankee lineup. But the psychological blow of that defection would be insane -- way more intense than Johnny "I'll never play for the Yankees" Damon.
Also, read this incredible Boston Globe story about the unravelling of the 2011 Red Sox. It's actually an unfair piece. As Terry Francona observes at one point, had the Sox actually lived up to expectations, accounts of how Josh Beckett blew off workouts for buckets of chicken would become hagiographies about how a three-time World Champion pitches too effortlessly for the minutiae of exercise. It wouldn't be about team laziness, it would be about how Papelbon showed up for optional training sessions.
The irony, the one that cuts Red Sox Nation to the quick, is that the Red Sox in 2011 are where the Yankees were from 2004 to 2007. An overpaid club addicted to overspending on marquee free agents in the hope of replicating an astonishing World Series run, burdened as the winningest manager in its history loses control, and unable to address its poisonous locker-room culture. And yet the club still contends every year, removing much of the incentive to change.