Throughout this offseason, the Diamondbacks have made it clear that they want to contend now. They didn't want to wait for their prospects to be ready, and instead, decided to go full steam ahead to try and win in 2016. By signing Zack Greinke, and trading for Shelby Miller, they've undoubtedly helped increase their odds of making the playoffs this season; but once the rest of the team is analyzed, those additions likely won't go as far as Dave Stewart and Tony La Russa are hoping they will.
Going into next season, the Diamondbacks are doing all they can to get their fans to focus on the core of Greinke, Miller, Paul Goldschmidt, and A.J. Pollock. Last season, that "core four" posted an fWAR of 25.2, which was the best in baseball. Moving forward, there's little reason to expect those numbers to crater, and with a full-season of Corbin, they could be even more valuable.
Despite those players, the Diamondbacks still have a considerable number of holes in their starting lineup, and even with a talented core, Arizona might not be able to overcome their significant shortcomings.
Outside of Goldschmidt, the Diamondbacks' infield is brutal. Heading into 2016, they're counting on Jake Lamb and Brandon Drury to take hold of third base, which neither player was able to do last year. That doesn't mean they won't this year, as both are top prospects in Arizona's system. In 390 plate appearances in 2015, Lamb hit .263/.331/.386, and seems like the more likely of the two to breakout in 2016. He posted a wRC+ of 92, which is just eight percent below league average, and thanks to his defense, Lamb finished with an fWAR of 2.0.
While it remains to be seen how Lamb and Drury will improve next season, third base isn't the most glaring issue for the Diamondbacks; it's the middle infield. Arizona is currently set to have Jean Segura at shortstop; who Stewart deliberately traded for.
"'What I like most about [this deal] is that we added a guy who can give us some offense after we lost some', said Stewart, indicating that the acquisition of Segura came in the wake of having to ship outfielder Ender Inciarte to Atlanta in the deal for right-hander Shelby Miller. '[Segura] gives us a top-of-the-lineup hitter and some speed. And he's a good defensive player.'"
It's not entirely out of the realm of possibility that Segura will hit well in 2016, but there's absolutely no evidence for it. Over the course of his career, Segura's slash line is .266/.301/.360, which is not who you want hitting at the top of a lineup. He's produced an above average OBP just once, and his wRC+ has routinely been awful. Stewart also mentioned Segura's defensive ability, and while he's been a good shortstop, Nick Ahmed grades out as the better fielder by far.
There's also the matter of second base, where Chris Owings is starting. In 552 plate appearances in 2015, he hit .227/.264/.322, and posted a wOBA of .255 and a wRC+ of 52. He has't provided any offensive value over the last two seasons, and like Segura, there's no reason to expect a change. Stewart was unwilling to part with another draft pick, and missed out on Howie Kendrick, who ultimately signed for a bargain at 2 years $20 million.
For the most part, the Diamondbacks' outfield is great. Pollock has quickly become one of the best center fielders in baseball, and David Peralta had a breakout 2015 season. Yasmany Tomas on the other hand did not have a good season. After signing a six-year deal worth $68.5 million, he hit .273/.305/.401 with a wOBA of .307, and a wRC+ of 88. According to FanGraphs, his raw power grades out as a 70, and his future value is 50. It's not impossible that he'll be valuable in 2016, but it's difficult to place faith in him. Tomas' production dramatically decreased as the season progressed, and there were very few signs of hope for the outfielder.
Based off FanGraphs' projections, the Diamondbacks are set to finish with a record of 79-83. While that shouldn't be taken as gospel, as Royals fans are all too aware, it still means something. Arizona will need various players to outperform what's expected of them, and while that could happen, it's not something we should count on. Stewart and La Russa helped thrust the Diamondbacks into the spotlight, but they failed to address too many needs.