Defensive "Deficiency": The Red Sox D ain't what it used to be?

According to Baseball Prospectus' Defensive Efficiency metric--which measures how often balls in play are turned into outs--the Red Sox just aren't getting the job done.Theo Epstein and the rest of the organization have been adamant about keeping a solid defense on the field.  And they have stressed it again this season, at least in terms of personnel.  But the team just hasn't been getting to balls as often as they have the passed few seasons.  They are currently 27th in the Majors in regards to the metric (DE), and 13th in the American League.  But again, the personnel, it is there.  In center, Jacoby Ellsbury roams full time and has not been poor by any means.  However, his 3.2 UZR/150 (3.2 runs saved per 150 games), has been far from great.  Ellsbury makes spectacular plays, and doesn't make many mistakes on the defensive side of the ball.  But the young CF is still learning how to run routes, and has been adjusting to the ...