That's the root cause.
If Breslow signed Teoscar, and he got hurt, would we be any better off right now?
It was far from a perfect off-season, but at some point this season has really been run by injuries. The Sox projected starting infield of Casas-Grissom-Story-Devers has not and will not play a single game together this season. Their biggest itcing addition will give them 0 IP.
Breslow has been somewhat lucky with regards to the depth he has added. It's not often you have a player go down with an injury and another team DFA's a player at that same position that was an All Star 2 years ago. But it has been silly. There's all kinds of unexpected developments based on PA alone. The Sox never at any point in the season expected Enmanuel Valdez to have more PA than Casas, for example.
I think Berslow was weak when it came to adding depth, but his overall plan, when uninjured, was not that bad...