They are on the block in a deal to bring in a superstar. They aren't on the block for what the C's are offering.
Now, the C's could potentially slip into a deal as a third team, but its unlikely.
But just to play along, I would go with Battier. I am not a big fan of Ariza's attitude, and his game doesn't blow me away either. But Battier would be perfect on the C's, and he comes off the books next year, if things don't work out.