Unless they trade for someone, I would say that Arroyo is pretty safe. As mentioned before, he has had some bad luck. The only time I remember him getting shelled was in a home game against Oakland. He has had some decent performances that have resulted in no decisions or losses. His last two wins were gems, 8 scoreless innings of work, but they came very far apart.
I see Kim as a nonfactor. He has been getting lit up. I don't see him making a great comeback.
Of course, the trade issue is the one that concerns me most. Theo is an aggressive guy that just doesn't sit around. I have a feeling he will go out and get someone before the trade deadline, although it probably won't be Randy Johnson. The Sox might end up with a Kris Benson or someone else of that mold, although I hope they learn from last year's Jeff Suppan mistake.