The Red Sox are 2-0-2 in their last four series, having won eight games and lost six. It's not great, but it's certainly not bad.
Except that it is. Because we're in the AL East, and three of those four series were against bad, bad teams, and even the Athletics are just skirting .500. These are the teams the Red Sox have to beat—badly—if they want to contend in this ridiculous division. Last year, they went 16-2 against the Orioles. This year, they are 4-5. That's not going to get the job done.
These last two weeks were another wasted opportunity, like when the Red Sox were swept by the Orioles earlier in the season. Instead of reasserting themselves into the division race, they found themselves (almost mercifully) another game back. While the Rays did not gain any ground this time around, the Yankees stretched their Wild Card lead by a game. The Red Sox went backwards when they needed to go forwards.
Perhaps the most frustrating part of this mediocre run is that there's no easily diagnosable problem. One day the back-end of the rotation is blowing the start of the Royal's series, the next they're going deep into games and stifling opposing lineups. The offense put up 50 runs in one six game stretch before managing only less than a quarter of that in the next four. With the Indians in an 0-2 hole and the Red Sox poised to sweep with Clay Buchholz and Jon Lester on the mound, the Sox went dead against Justin Masterson, and then Lester managed to get shelled for six runs despite striking out eight, and Bard gets beaten up in the final inning.
This isn't to say the Red Sox are doomed, just that they've made their jobs much, much more difficult. Instead of having to defeat the cellar dwellers of the world, they have to perform against the harder competition coming up from the AL East and NL West. They have shown they can do so since the turnaround—the 9 games preceding this "easier stretch" are proof enough of that. Now they have to go out and do it again.