If nothing else, this move gives them a contract that they can drop next year in an effort to open up money for a FA pitcher like Hamels or Cain (assuming they don't get extensions, etc.,). With Dice-K, Jenks and Scutaro all coming off the books at that time, they would be looking at something like $35m coming off the books. Hopefully with another year of Kalish/Reddick, Lavarnway, Middlebrooks, Iglesias or Lowrie all finding a spot, they will have just about every position locked down and could use most of that money on the rotation.
It's wishful thinking, but is a reasonable rationale for their approach.
Also, as far as we know, they could have other things up their sleeves for 2012. NWIH they are planning on just sitting around hoping things go well, and wasting the prime years of guys like Lester, Buchholz, Gonzalez, Pedroia and Ellsbury.