That's just weird reasoning. Boras has as much interest in getting this deal done as Boston does, or as Seibu does, or as Matsuzaka does. If Matsuzaka goes back to Japan and hurts his arm next season he's looking at NOTHING. Not 51 million PLUS his contract, but nothing. Now you think about it: is Boras such a dumb ass as to take the ONLY team that is guaranteeing 100 million dollars to his client (on a short contract) and shut them out of negotiations? No. He's not. He's rich and smart and he understands game theory enough to know that, in many situations, it is not a winner take all scenario. In this case there is no winner to be had from ANY scenario, either everyone wins or everyone loses.
In an everyone wins or everyone loses scenario the chances are TREMENDOUS that everyone wins. You think Seibu is willing to throw 10 million in to make the deal happen? I do. You think Matsuzaka is willing to NOT be the higest paid pitcher in baseball? I do. You think the Red Sox are going to ensure that Matsuzaka gets every possible creature comfort, every provision, every chance at the nicest apartment, car, parking spot available? I do.
It is such conspiracy theory crap to think the Red Sox would lowball Matsuzaka with the intention of a "take it or leave it, we're not flexible at all" stance.
Not a chance in hell that this deal doesn't get done.