I actually think his footwork is a primary problem. He is in love with throwing on the run. When you charge a softly hit ball at short, then fine, you have to throw on the run. Other times, set your feet, turn sideways, and make a throw. He does the "run across the bag and throw off balance" at 2nd base on DPs way too often for example. Take a crow hop instead, planting your front foot on 2nd as you make a normal throw to first. I think his whole throwing motion contributes to his weakish arm, compounding the weakness with inaccuracy.