It began with an innocuous piece of Winter Meetings gossip in the middle of what was already a day of frenzied activity.
The teams had been connected for the entirety of the Meetings, related to Braves' starter Shelby Miller. However, after the surprising mega signing of Zack Greinke by the Diamondbacks and Atlanta's insistence on A.J. Pollock included in any deal, a trade seemed anything but certain.
Then, rumors that a deal was close, but that Pollock was not involved. Following that, an update stating that breakout outfielder Ender Inciarte and other players were the return, and it seemed like a pretty reasonable deal for a young starter worth 3.4 fWAR with 205.1 innings pitched in 2015.
Then, it got kind of crazy: reports emerged that the full trade was actually Inciarte, 2015 first-overall pick Dansby Swanson, and top pitching prospect Aaron Blair for Miller and minor league pitcher Gabe Speier. Swanson and Blair currently rank as the 10th and 61st best prospects in all of baseball, per MLB.com's Top 100 List.
It is a significant haul for Miller, who is a very good pitcher, but not the often considered an "ace." He had his best season to date in 2015, but still was only tied for the 25th-most valuable pitching season in the majors. His 47.7 percent ground ball rate in 2015 was better than league average, but he walked an above-average number of batters (8.5 percent) while striking out a roughly average amount (19.9 percent).
In Miller's favor are his age (only 25), length of remaining team control (three seasons), hard velocity, and durability. Miller has made at least 31 starts in each of his three full seasons, and averaged 94.1 MPH with his fastball in 2015 (tied for 14th-best in the majors, per FanGraphs). However, he doesn't miss a lot of bats and his 9.2 percent swinging strike rate was both tied for his full season best, and almost exactly league average for a starter.
One thing to watch with Miller in 2016 will be his four-seam fastball. He relied more heavily on the pitch as 2015 wore on, and saw a consistent velocity drop and flattening out of the pitch throughout the year.
However, given Miller's age, electric stuff, durability, and above-average performance, he's probably still a great pickup. The far more controversial question is whether he is actually worth the monumental package that Arizona gave up for him.
In fact, the key major league piece received by Atlanta in this deal, Inciarte, was himself worth 3.3 fWAR in 2015 -- roughly equal to Miller's production. He is also 25 but has five more seasons of team control (including 2016) and will likely cost less in arbitration due to deriving so much of his value from defense.
That defense is also far more prone to fluctuation and less reliable than other forms of value in WAR, so it is completely reasonable to believe he is a less valuable player than Miller. Given the prior demand of Pollock, a shadow down-ballot MVP candidate, losing Inciarte goes down much more easily for the Diamondbacks.
The second piece in the deal is the far more controversial one. The first-overall pick in the 2015 draft, Dansby Swanson was probably one of the last players in the entire Diamondbacks organization that anyone expected to move. As noted by Scout Media reporter Taylor Blake Ward, he joins prestigious company with this trade.
Dansby Swanson could become first #1 overall pick to be traded before MLB debut since Adrian Gonzalez (drafted 2000; traded 2003)— Taylor Blake Ward (@TaylorBlakeWard) December 9, 2015
He also joins Brady Aiken as the second straight player to not make their full-season debut with the team that drafted them first-overall. He's one of the dozen or so best prospects in the game, and his inclusion is kind of surprising to return a talent that doesn't perhaps qualify as "elite."
The third piece in the deal, Aaron Blair, was the Diamondbacks' first-round pick in the 2013 draft. He was ranked by MLB.com as the third-best prospect in their system, and is a consensus Top-100 prospect. He falls in line with the Braves' noted strategy of collecting as many high-upside Minor League arms as humanly possible. That strategy was also seen last season as the Braves acquired Touki Toussaint from the Diamondbacks -- meaning that each of Arizona's last three first-round picks (2013-2015) have been traded to Atlanta.
Shelby Miller is probably the best player in this trade today, and there's an old adage about the team who receives the best player is the one that wins the trade. However, with the plethora of value sent over in return, it is hard to imagine a scenario where total expected value doesn't favor the Braves.
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Spencer Bingol is a Featured Writer at Beyond the Box Score. You can follow him on Twitter at @SpencerBingol.