There was that one stretch in Sept. where Nathan pitched 3 days in a row, and he got the loss in the 3rd game. There were two other periods earlier in the season where Nathan was called upon to pitch either 3 or 4 days in a row. Having a guy with closing experience like Soria who can step in for Nathan on that 3rd or 4th day ensures Nathan isn't taxed too much. And with Soria signed for '14 when Nathan will be a FA, we could have Nathan's successor at closer in place.