I disagree with this. Hanrahan, Bailey, Miller, Wilson were all late inning bullpen options that were hurt. The starting third baseman was very ineffective the first half of the year. Their top CF prospect started in the majors and pretty much fell on his face, and depth option Kalish had season ending surgery again. Their franchise DH started the season on the DL, and the team's ace spent most of the season on the DL as well. The guys he traded away -- Gonzalez, Crawford, Melancon and even Punto have been very successful. Hell, there was a national tragedy one mile away from the stadium.
The reason why the Red Sox have been successful is that Ben built a considerable amount of depth. Guys that some called unnecessary, like Drew, Gomes, Dempster may not have been superstars, but when more significant players have been hurt, they've filled in well, and they've played much better than replacement level AAAA guys would have.