Estrada also had a DL stint and has had a bad back and it's not quite the same as pitches thrown vs IP. I understand the difference you're trying to say regarding strain on the arm but if you get taken out in the 3rd inning after getting roughed up in a tough 50+pitches outing, that can be just as exhausting or more than a 100 pitches 7IP game of clean ball with regular rest.