Why can’t the Dodgers put a finger on Rich Hill’s blister problem?

There's a learning curve on how to bide one's time on a disabled list. Rich Hill, thanks to his curveball, is accelerating in this practice at a blistering pace.Strange, but can anyone put their finger on what exactly is causing him problems throwing this high-spin-rate pitch at the mature age of 37?When big-league pitchers of a certain age are trying to save their careers, isn't this where a knuckleball is suggested, not something that will require extra torque and twist - and that's just Hill trying to stick the landing after he delivers it.