The third baseman is ... struggling. Let's examine what kind of leash he has.
Dave Cameron recently wrote about Casey McGehee hitting leadoff for the Giants. He did this because he hates you and every single Giants fan on the planet. But he also did it because he was looking for a way to minimize McGehee's double play problem. The article includes these words:
So when you take into account the negative value of the extra outs McGehee is making by hitting into double plays -- and at FanGraphs, we have a metric called RE24 that does just that -- we find that he's been the very worst offensive player in baseball to date
/faints
The numbers back up what you were expecting, then.