The Rays' secret weapon

Believe it or not, Jason Bartlett's glove might be the key to the Rays' playoff hopes. Getty Images

It's no secret that there's been a greater focus on defense in baseball the last few years. Much of this came from the 2008 Rays, who rode an improved defense to one of the most surprising postseason appearances in baseball history.

Over at Baseball Info Solutions, we've embraced that shift and created the Defensive Runs Saved metric, which measures each player's defense relative to the average player at his position. As the second half begins, it's important to note that defense could once again make the difference in a number of key playoff races. To illustrate that, we've broken down every infield in baseball into pairs. Here are the best and worst pairs of the first half. If these numbers hold, the Rays have a major defensive edge in the AL East.