The star power of this Diamondbacks team is a little different than in years past. Justin Upton and Chris Young are gone. The team is now populated by "grinders" like Martin Prado, Aaron Hill, Willie Bloomquist, Cody Ross, and Adam Eaton. Of course, there are still some remnants of the old guard in Arizona, and I think one of those holdovers is going to make a huge impact in 2013.
My x-factor for the Arizona Diamondbacks in 2013 is Paul Goldschmidt.
Goldschmidt absolutely brutalized the minor leagues in 2010 and 2011 before getting called up to the majors later in the 2011 season. Goldschmidt's power hasn't completely translated to the majors yet though, as in 764 career plate appearances, he had 28 homers and a .209 ISO. The league average ISO for a first baseman in 2012 was .179, so Goldschmidt's power wasn't exactly Bautista-esque in comparison to the rest of the position.
However, there's a huge opportunity for Goldschmidt to continue to succeed in 2013, and that's against left-handed pitching. Over his career, Goldschmidt has a .996 OPS and .287 ISO against southpaws, compared to .769 and .174 against righties. The NL West is loaded with quality left-handed starters, including Jorge de la Rosa, Drew Pomeranz, Clayton Kershaw, Hyun-Jin Ryu, Clayton Richard, and Madison Bumgarner. Goldschmidt can absolutely destroy those guys while playing every day, along with holding his own against the other right-handed starters in the division like Zack Greinke, Chad Billingsley, Josh Beckett, Edinson Volquez, Matt Cain, and Tim Lincecum.
Another good thing about Goldschmidt is that he'll likely have Jason Kubel hitting behind him. Kubel has a platoon split the inverse of Goldschmidt's, in that he destroys righties but struggles against lefties. And hitting ahead of Goldschmidt is Miguel Montero, who has worse stats against lefties than righties. Essentially, by sandwiching Goldschmidt between a pair of lefthanders, the Diamondbacks are going to be able to throw opposing bullpens into chaos and potentially get teams to waste relievers on one hitter, or risk getting smashed to hell.
If Kirk Gibson sets his lineup properly the middle of Arizona's order could be a murderer's row, and Goldschmidt could turn into one of the best power hitters in the National League with Montero and Kubel surrounding him in the order.