For the most part I agree what you said, but Okajima with an "off year" should still translate to a 3.5 ERA reliever, IMO. So his "off year" will only be in comparison to this year.
Delcarmen had TJ surgery a few years back, and I think the organization made the decision to keep him in the 'pen as a result.
Besides, with Okajima regressing as he has, it's nice to have another reliable arm out of the 'pen.
Did you see Stuart Scott rapping a highlight?
http://bp0.blogger.com/_1ZKIESoXB4E/Rw2hlDH15SI/AAAAAAAADVM/mzFssiSJwe4/s1600/Image1010-2101(TV27)%5B1%5D-768038.jpg