I'm arguing the 2.8%increase in K% is injury related and not lack of focus or declining trend.It is fair to expect an increase after the time he missed.Just because your already prone to strike outs doesn't mean you aren't going to have even more trouble after a major injury.Your "June 1st 2017 until he got injured"BB% theory was mostly a terrible July of 5.6%, June and August were close to his 2016-2018 average.He is not the first player to have a bad month.Ups and Downs can be expected for young players. So when he puts together an 18.6 BB% for the month of April 2017, that is not the real Sano.Just like a 5.6% in July 2017 is not the real Sano.(The 2017 BB% trend of a good start and poor June/July was almost identical to his 2016 trend FYI)
Staking your perception on a half season of his rookie year isn't the best approach.Especially when he was out performing his AA BB% and on base%.
Look, I don't want to get lost in the weeds here but it's not just about BB%. As I said, that stat is symptomatic of larger discipline trends. His plate approach in general has deteriorated drastically since he was a rookie. There are any number of stats that illustrate this — not just his propensity for getting into certain counts, but what he does when he gets there. Glaring weaknesses in the strike zone. Pitcher adjustments that haven't been counteracted.
And while it's convenient to brush off last year's struggles as the result of health problems, the convenience fades when you recognize we have no proof those serious, structural problems are behind him. Sano was evidently never healthy last year, and for a second straight season he finished hurt. We still haven't seen him on the field yet this spring to alleviate any such concerns.
(Also I'm not sure why Sano's age-22 season in AA has become his baseline/ceiling for patience; his walk rate in the minors was only slightly lower than Joey Votto's. One hopes to see a player of this ilk evolve, not devolve.)