This is a really great read and it seems very believable to me, without any stats to back me up, that Dex playing too shallow has hurt his defensive value. He's athletic and seems (again all anecdotal) to get good jumps on balls. I'll definitely trade a handful more singles over giving up doubles and triples over his head. Yeah, I'll trade the singles all day in order to take away some extra-base hits over his head. It seems really counterproductive to play that shallow in order to stop some balls from falling in front of you. It also seems like playing shallow would shrink his range down artificially, because balls hit deep or going to tend to hang in the air longer. So the extra balls he could get to by playing shallow aren't going to hang in the air as long. Which means, he has less time to cover ground. And that means his probable catch zone radius is going to be smaller. I wonder if we have any data to back this notion up. Statcast is going to be a great tool to help with defensive positioning. You can plot how often a ball is hit to every spot on the field and how long the ball hangs in the air, and then come up with the optimal spot to stick a guy, based on a catch probability zone. It's also much, much easier to get to balls in front of you than balls over your head, playing dudes shallow seems to make little sense to me, but I await more learned gentlemen with more evidence to show how wrong I am.