I personally think that more of the issue is batters faced / pitches thrown in a given month/rolling window. If, through a combination of keeping his starts more in the 5 inning range, and giving him priority for the extra rest days to push back his starts while keeping the other starters on regular rotation will keep him from being overtaxed at any given time. With that sort of model, I think the risk in pushing past the "book" on innings increase per year wouldn't be all that high. Granted, there is truth to "hitting the wall" as players go into September/October when they never have before, but I think having a rolling look at his workload so that he's never getting to a point of being overworked at any given time would help alleviate that as well. If at any point it seems his hitting that wall a bit with fatigue even at all, 10 day DL and skip a start or 2, and that would help all around as well. We just have to make sure not to "Eldred" him to 250 innings or something ridiculous.