They thought this was going to be a "bridge" year, but baseball can sometimes be unpredictable. They are a surprise team--maybe overachieving. But so did the Orioles last year, and it turned out they are really pretty good. No fluke there. So maybe the Red Sox are pretty good.
My guess is they have changed their thinking somewhat about this year, and are more inclined to fill holes because they are in the thick of it. At some point, the Rays figure to cool off, so you know they aren't going to create much distance.
One thing that bites them is having a SS type hitter playing 3B. As long as Iggy was hitting .400 it didn't matter that Drew continues to suck as a hitter at SS, but now that Iggy is coming back to earth (as any hitter does in this situation), the problem is showing up. They need more lumber at 3B, where hitting is more important than defense.
When Drew got hurt again, they moved Iggy to SS, and got some hitting from Snyder and Holt at 3B. But they both made important errors in games.
With the talk now of using Middlebrooks as a trade chip, you wonder if it wasn't better to bring him up when Drew got hurt, and tolerate his weak OBP. He isn't much worse hitting than what Drew has been. And better defensively than the replacements. Even Iggy has shown a weakness in fielding bunts, which SSs don't often do.