Rob Peter to pay Paul. Weaken the starting rotation to boost the bullpen. The Sox bit the bullet, moving Jonathan Papelbon back to the back end, and in doing so, strengthened their overall pitching. Obviously, the brain trust feared that they would be wasting efforts deep into the game by Schilling, Beckett, and Matsuzaka without a premier closer. And Papelbon had an Eckersley-like run before injury shut him down.
If the Sox can identify (or acquire) another closer at some time, then they can relocate Papelbon to the rotation. And the cost just went down, as dealing from weakness, you always end up dealing more than you want.
Julian Tavarez pitched effectively down the stretch last season, going 3-0 with a 3.52 ERA last September, a small sample size. Maybe he can at least fill the gap until either John Lester or another candidate for the five spot emerges, or another closer evolves.