Sure, but that doesn't change the math about moving a starter to the bullpen -- especially a competent SP.
Just because the A's did something, that doesn't mean it's a good idea, even if it worked. They tried all sorts of wacky crap, whether it's Charlie Finley, Tony La Russa, or Billy Beane, they always seem to attract that sort.
Hard to say Eckersley couldn't have been as useful as a starter if they could pull a half decent closer. Especially outside the 4-5 years he's really known for as a closer.