What Happened to the D-Backs?

     Over the offseason, the Arizona Diamondbacks signed one of the best pitchers on the planet, traded for a solid, young arm and continued to employ one of the best players in the league along with an underrated rising star outfielder. Even if they weren't the favorites in a tough NL West, it looked like they would at least contend. Now, they're in fourth place with a record of 65-91, sitting in dead last. Obviously, things went very, very wrong. Lets take a look at what those things were.
     There are so many reasons for this garbage fire of a season, but one of the main ones is A.J. Pollock's injury. The centerfielder had a breakout year in 2015, batting .315/.367/.498, hitting 20 homers and stealing 39 bases, all while playing Gold Glove level defense. He tore an elbow ligament in Spring Training, knocking him out for almost the entire season. Having traded away their 2015 right fielder Ender Inciarte in a deal for Shelby Miller, (more on that debacle later) the D-Backs suddenly found themselves short on outfielders, having to rely on the washed up Michael Bourn before trading him to Baltimore.
     The aforementioned Shelby Miller trade is another reason Arizona's underperformed this year. We'll get to who they gave up in a second, but we knew it would likely be bad in the long term. What people weren't expecting, was that to the horror of the Diamondbacks' higher-ups, Miller was a complete disaster this year, posting an ERA of 6.90, setting career worsts in just about every stat, and was basically a poor man's Ricky Nolasco.
     It was a bad trade that's only going to get worse as time goes on. Atlanta made off with shortstop Dansby Swanson in the deal. The 2015 number one overall pick is considered to be right up there with Carlos Correa and Francisco Lindor as the top young shortstops in the game. So far in his young career, Swanson has hit .300/.347/.400 while providing steady defense at short. Did I mention he's 22 years old? Now, trading a shortstop that young and that good straight up for Shelby Miller is egregious enough, but Arizona also lost Ender Inciarte in the deal. Inciarte had a solid season in Phoenix in 2015 and is now one of the few steady presences on the Braves, hitting .299/.355/.388 with 16 stolen bases.
     All this is bad, but it shouldn't have undermined the season, losing Pollock hurt the most out of those, but what has ruined the Diamondbacks season more than anything else is simply that players they were counting on haven't delivered. Zack Greinke was a top three pitcher in all of baseball in 2015, barely losing out on the Cy Young to Jake Arrieta. This year has been a different story, to say the least. His 4.37 ERA puts him in the same neighborhood as guys like Doug Fister and Ricky Nolasco. (Damnit did I just compare two different guys to Ricky Nolasco in the same column?) His 2.2 WAR has him making 15.5 million dollars for every win he brings to the table. For comparison's sake, Kris Bryant is making roughly 74 thousand dollars this year for each of his 8.4 wins. Admittedly, he had been doing better before going on the DL in July, but even then, he was nowhere near the standard he had set over the last few years, sporting an ERA of 3.62..
     When you go to the advanced stats, there are a couple of potential reasons for this. One is his move to the hitters park that is Chase Field from the decidedly more spacious Dodger Stadium. That could explain why his homers per nine innings have spiked from .57 to 1.30 this season. Another is that the Diamondbacks rank 18th in baseball in defensive runs saved this year with -11. It isn't terrible, but it's still nine runs worse than the 2015 Dodgers. Those don't totally explain his fall, there's still a lot of mystery, but it at least provides some information.
     It wasn't just Greinke disappointing either. Miller, Patrick Corbin, and Robbie Ray all had ERAs of at least 4.77 despite the fact that they're all under the age of 26 and all have had seasons with ERAs under 3.60. In fact, the starting rotation as a whole had a collective ERA this year of 4.37, eighth worst in the league. No matter how much Paul Goldschmidt is raking, it's hard to win with the other team scoring that much.
     Everyone knew the NL West was going to be tough this year, with the Dodgers coming off of another strong season and the Giants making improvements (along with it being an even year), so even after the D-Backs signed Greinke and traded for Miller, it was tough to say how much they would contend. After a full season of those guys on that team, we now have the definitive answer: None.