Nobody's closing the book on Turner, obviously, but in the context of this article, he's clearly failed to develop overall *this year*. He's the worst hitting catcher in AA baseball (min. 200 PA): http://www.fangraphs.com/minorleaders.aspx?pos=c&stats=bat&lg=5,6,7&qual=200&type=1&season=2015&team=0&players=0&sort=18,d 7 guys above him 23 and younger too. Drop the PA threshold to 100 and 4 more guys 23 and under jump ahead of him... However much he may have developed with the glove or game-calling or whatever else this year, he has almost certainly taken an equal or greater step back offensively. Hence "failed to develop", overall, this year. If he finds success again next year, it will be in spite of 2015, not because of it.