The Red Sox clinched the American League East last night. A lot is being written about their quick turnaround, which is probably appropriate, considering they lost 93 games last year and traded one of their best players. The how is pretty interesting, and I encourage you to check out this piece from the tireless Alex Speier of WEEI.com, and really any of the work Speier has done this year. He's done a ton of great work and seems to have a lot of access, so I'm hoping he writes a book when the season is said and done. He can be a little uncritical at times, taking the words of team officials at face value, but face value can be informative and helpful, especially when written so well.
I won't get into the how of the roster construction, however. I don't have the access for such a thing anyway. What I just wanted to point out was the why. The Red Sox are good this year because they basically have an entire team of good players. The Red Sox have eight players with a rWAR of at least 3.0, and 17 at over 1.0 (including the now-departed Jose Iglesias). By the same measure, they have the fifth (Pedroia), seventh (Victorino), and ninth (Ellsbury) best position players in the American League.
When every single player on the team is good, the team wins. That some of the players have played over their expectations (Victorino, Nava, Uehara) is helpful, but the team is full of good players having good seasons. That's easier said than done, but the success is probably less surprising than it should have been.