Lin, Rutledge, and Marrero are not third baseman and never will be. Sandoval just isn't anymore. Getting 0 from them of late puts pressure on DD that none of us want to see. We all know what that means. He is trying not to trade for one, but I would not be surprised if it happens just out of necessity.
As for players who are "supposed" to be hitting - I don't buy it but I don't like to assume things. I expect a little more from Betts I guess but Hanley is Hanley folks. He was fine with Ortiz in the lineup and dugout but without him there, people need to temper their expectations for him. As this team was constructed, i think that we are getting about what we can expect. We all knew that it was going to boil down to the pitching staff remaining healthy which it hasn't. In hindsight, it would look like a mistake was made in not trying to replace Ortiz's bat. Moreland has been better than I thought he would be but outside of Betts the rest of this order doesn't surprise me at all. Counting on Sandoval coming back strong really looks like the big mistake here.