Your judgment, but certainly not mine. Right now the Sox defense is an asset, especially in the outfield, at catcher, at 3b, at SS, and even at 2b when Hamilton or Rafaela is there. 1b is the only problem, and even there I'm not sure it is. Seriously. When I watch the games, I regularly see our first basemen make good plays, and all are better than Casas. Yesterday Gonzalez started a nifty double play when the fielded a grounder, ran to first, and then made a perfect throw to Story, who tagged the runner out.
I think you under-rate Story at SS. To me he has been reliable on throws to 1b when going to his right,on charging in on slow rollers, going back on popups, and turning double plays. Cora has started Story in 106 games, 2d most on the team. And he did that despite Story's struggles at the plate which hopefully are over. Thus does Story leads MLB shortstops in total chances, assists, and double plays. He is 2d in putouts.