When I first read this I thought definitely but after looking at your team I dont think I would.. I really believe in Gio this season and Craig will be back soon you also would take a noticeable hit in pitching which may do more harm than the advantage of getting Fielder. Check this out: viewtopic.php?t=448083
Brother with CC, Bumgarner, Marcum, and Sanchez leading your rotation that there is sick enough. You easily have enough pitching depth to pull the trigger. You have to do this deal. Any good rotation is lead by 2 stud starters well you have 3 in CC/Bum/Sanchez, 2 solid ones (marcum and wandy) plus Norris who is having a solid year. Niese is probably droppable but you can stream 2sp there at worst.