I haven't read anything but the snippet quoted, but I have serious doubts that a new pitching coach will improve walk rates, and have even more doubt that bringing a new pitching coach in with the clear charge of "you must improve walk rates" is anything but a terrible idea.

Why do you think the charge would simply be "you must improve walk rates"? Couldn't it be the particular approach they used led to more walks (i.e. certain pitches to start counts, the sequences, etc), so they want to do something different and it sounds like Bosio wasn't that willing to adjust?

I don't really think that's the charge, but the article makes it sound like the coaching and the walk rates be two sides of the same coin. And I am very skeptical about that.

The team walk rate has indeed spiked: it went from 2.5/9 IP in 2015 to 3.1 and now 3.5. Perhaps there is some very specific flaw about the current approach that is behind that, but my guess is that it is mostly about pitchers who have always given up a lot of walks giving up even more.

Oh, I'm sure it's multiple things, including talent. It'll be interesting to revisit this next year.

Test.