For me at least, it's not just the 8 game slide, it's the complete and utter incompetence at the plate when facing any left handed pitcher. I thought "ok, they faced Price and Moore. Fine, I understand struggling against them"
But then it's Chen, Buehrle, Pettite, Oborholtzer, guys you've never heard of in your life. It's Ortiz OPS'ing .727 vs LHP when he OPS'd .985 against them last year. Johnny Gomes OPS'ing .730 vs LHP. Victorino OPS'ing .756. Napoli OPS'ing .761. Even Ross, who is supposed to spell Salty vs LHP is only OPS'ing .728.
Hell, we've had 3 hitters OPS over .800 vs LHP this year, and 2 of them aren't on the team anymore (Iglesias .842, Snyder .964). Pedroia (.890) is the other.
That's a massive, massive concern. As soon as the SP goes out, this team just gets absolutely pummeled by LH relief pitchers. And why not?? They have nobody who can even sniff a mediocre line against them outside of Pedroia.
It's funny, when the season began and we had Pedroia, Ortiz, Napoli, Middlebrooks, Gomes, Ross, and then the bullpen of Uehara, Taz, Bailey, Hanrahan, etc, all anyone said was "There are two things this team will do well, hit LHP and close out games late". And those are the two biggest struggles (though Uehara has been MVP worthy).