I usually try to avoid kicking a team too much when it's down, but Arizona's bullpen is something to behold. Not only are the D-Backs 23 games out of first place, but they are dead last in bullpen ERA in the ML by a wide margin:
29. Milwaukee 5.10 (16-16)
30. Arizona 6.59 ERA (9-21)
The only team since 2000 to finish with a team bullpen ERA over 5.55 was the Devil Rays in 2007 (their final season before shortening to just "Rays") at 6.16 (silver lining: the Rays finished 5th in bullpen ERA in 2008 on their way to the World Series).
One of the more worst stats is that their closer (Chad Qualls) has an of 8.51 ERA in addition to 12 saves. Qualls has been a durable, quality reliever for the last 6 years, and had never had an ERA over 4.00 before this year.
The only pitcher in ML history to complete a season with at least 10 saves and an ERA over 7.50 was Mike Perez in 1994 for St. Louis (12 SV, 8.71 ERA), and no one has done so with 15 saves.
Any signs of hope? A few.
Esmerling Vasquez: 1.86 ERA, 11 G in July (after a bad start)
Juan Gutierrez: 3.86 ERA, 18 G since June 1 (after an even worse start)
Blaine Boyer: 2.85 ERA, 17 G since June 1
Aaron Heilman: 3.60 ERA, 44 G this season
If Chad Qualls can get it turned around, they might finally have a small, somewhat reliable group of relievers they can go to and simply finish the season as a bad bullpen on the upswing rather than one of the worst of modern times.