|Leonys Martin - CF||Ender Inciarte - LF|
|Elvis Andrus - SS||A.J. Pollock - CF|
|Prince Fielder - 1B||Paul Goldschmidt - 1B|
|Adrian Beltre - 3B||Mark Trumbo - RF|
|Shin-Soo Choo - RF||Aaron Hill - 3B|
|Robinson Chirinos - C||Chris Owings - 2B|
|Jake Smolinski - LF||Tuffy Gosewisch - C|
|Rougned Odor - 2B||Archie Bradley - RHP|
|Yovani Gallardo - RHP||Nick Ahmed - SS|
Yes, do not adjust your eyeballs. That is indeed Archie Bradley, batting eighth for the Arizona Diamondbacks tonight. I'm not 100% certain whose idea that is, but I have a strong suspicion it isn't Chip Hale. I say this because our Chief Baseball Office, Tony La Russa, was famous for doing it intermittently while manager of the St. Louis Cardinals, and a study before the 2013 season had him, far and away, the manager who had done it most often. La Russa had used the tactic 432 times; no-one else at that point (and I don't think much has changed) had done it more than 74 times. Indeed, La Russa used it more than every other manager combined. So: this one's likely on him.
The theory behind it is this. While it will typically mean the pitcher's spot comes up a little more often, it also means the good hitters at the top of the order come up with men on base more often. The resulting difference in overall production is slight - practically infinitesimal - but it does exist. Another study took a conventional line-up based on the average hitter in each spot, and found it was worth an average of 3.7079 runs per game. When the pitcher and #8 hitter were swapped, but everything else remained the same, the line-up scored 3.7118 runs. Yeah, that's trivial - less than one run over the course of a season, but does go to show the "obvious" way is not necessarily best.
Of course, the irony is that our #9 hitter so far actually has been a worse hitter than our pitchers: he's batting (and slugging) .122, while the Diamondbacks' hurlers have collectively been hitting (and slugging) .125. Nick Ahmed's sole advantage in terms of offensive production is, he has been taking a few walks. Though given he has hit almost exclusively in the #8 spot, these may have been a (somewhat misguided) decision to pitch around him and work to the hitters - only one of his walks has been after the fourth inning. Given Bradley's career batting average of .167 (okay: he's 1-for-6), you could argue this is a conventional line-up after all.