is that, in 2016, the decline was consistent whereas in 2017, it *appears* as though he basically continued throwing what he started the season throwing.
But yeah, if his velocity is in precipitous decline (heralding major reconstructive surgery), he's one to keep far, far away from. That doesn't *appear* to be the case here, to my untrained eye. It *appears* that this version of Arrieta is simply 80% of the one that pretended he was peak Pedro Martinez for a whole season a couple years back.
As Doc would say, that's a whale of a pitcher--and an upgrade to any staff in baseball. I think there is enough concern about his health that 6+ year commitments simply aren't going to happen for him. He's a top candidate for a so-called 'pillow contract' *IF* his arm is, in fact, reasonably fine (for a 30+ year old MLB workhorse, hahaha). If his arm is NOT fine, however, he'll opt to wait out the market.
Might just be that my line of reasoning is one shared by a few MLB front offices, now that I think about it...