Despite throwing one fewer inning than Lieber, he has thrown 175 fewer pitches, the equivalent of about a game and a half. More pitches and more innings than Lieber, but Lieber has made more efficient use of his pitches. Chalk it up to all Johnson's whiffs. Glavine has thrown 60 more pitches than Lieber but some 10 fewer innings. It's the act of throwing the actual pitch that is unnatural and that creates actual wear and tear on an arm.
Pitches are the components of innings.
All innings are not created equal. We've all seen guys like Maddux get out of an inning with only three pitches. And we've all seen guys like Jason Bere use 40 pitches to get three outs. It's pitches that take the toll, not innings. 67 more pitches than Lieber, 15.2 fewer innings.