Its conditioning. Just like anything, if you want to do it at the highest of levels, there is work you need to do to be ready to do it. If you want to run a marathon, you don't get there by walking around the block a few times. You get there by scaling up your mileage over time so that you are peaking at 26.2 miles. Starting is the same way. If you want to make is through the slog of a 180 to 200 innings, you need to work your arm up to that. You don't go from 50 innings to 180. Rodon is running into the same problems.