THT is a wonderful statistical resource. One of the coolest things it does (to me, anyway) is post a daily-updated measure of team defense, broken down by groundballs and fly balls. Each team gets two plus/minus values, one for each category. For example, so far this year the Mariners have been -4 and -5, meaning they've turned four fewer groundballs and five fewer fly balls into outs than expected. It's a very simple, easy-to-understand rating system that I find to be remarkably accurate.
With that in mind, I give you the Tampa Bay Devil Rays:
Ground: -31
Air: -7
In 28 games, the D-Rays are at -38 outs. Over a full season, that's a difference of 220 makable plays that weren't. Using an approximate run value of 0.5 runs per play, that defense is on pace to cost the team more than 100 runs this year. Put another way, this group is roughly as bad as the 2002 Angels were good.
I don't know about you, but I just find that incredible. Tampa Bay's defense is on pace to make the difference between a fourth-place finish and challenging for the Wild Card. Next time somebody tries to downplay the importance of fielding when it comes to evaluating a certain team, don't pay them any mind. It's vitally important, and if you don't have it, chances are you won't live to see October.