While I would not call the Sox bench weak, it's difficult not to recognized that is poorly composed.
The Sox screwed the pooch on the Lowell to Texas deal and the handicap that resulted has remained to this day.
Hermida is a defensive nightmare and at best, a mediocre platoon hitter.
Hall has been serviceable in left and center but can't play SS and he may be nearly as bad at second (when we get enough of a sample size to make a fair assessment). As much as I love Mike Lowell, he's got no place on a team with three other 1st basemen and two other 3rd basemen.
As for Lowrie, he was never in the plans for the Sox during the winter. The plan for him from all reports, was to be in Pawtucket demonstrating that his wrist could withstand the rigors of daily play and to regain his hitting ability from the left side.
Obviously, that did not happen.
The Sox did make two good moves. Acquiring McDonald, and promoting Nava. Both have been all that anyone could have expected.
Anyone that believes that Pedroia will be back (and productive) in 4-6 weeks needs to have a better understanding of human physiology. The bone that he broke is load bearing and has poor blood supply. That means it won't heal as quickly as some other bones (see the post by Jacko) or review your college physiology text.
Pedroia will be on the field at Fenway in 6-8 weeks if all goes well. In the mean time, a real, proven MLB offensive replacement with average or above average defense needs to be acquired.
I say go after Ty Wigginton.