Stubbs offense is more than a little troubling at the moment. His contact rate is < 65% and his K rate is > 40% (if you want a comparison Dunns worst K rate ever was 34% and contact rate was 70%). There is no way Stubbs can have offensive success at anywhere near those rates.
Carbrera currently has a UZR/150 of -36. That is off the charts bad and this correlates with what observation has been providing, Cabrera isn't getting to anything. His defense took a huge step backward in 09 (not unusual for a mid 30s SS) but it has gotten even worse this season. There is really no way then can win with that kind of play at SS.