The biggest surprise of 2011, the Arizona Diamondbacks overtook the defending champs and won the NL West, going 94-68. Both their pitching and hitting was average, but they played great defense and had a little luck, finishing 6 games better than their Pythagorean record. The entire core of the team returns, making them the divisional favorites for 2012.
Justin Upton is the face of the franchise, still only 24 years old and possessing skills matched by very few. He has mammoth power, yet can still run and play good defense in right field. His walk and K rates have fluctuated greatly so far in his career, with each of them being at a career low last year. If he can keep his strikeouts down, he should be able to maintain a 5-6 WAR level. In center field, Chris Young combines good defense and power to about 4 WAR a year. His average will never be great due to his high K rate and flyball tendencies, but he walks at a double-digit rate. Jason Kubel was signed this offseason, hoping to provide another power bat to the lineup, though his expected playing time is not known. After a career year in '09, he has barely stayed above average the last couple years, with a decrease in plate discipline last year. If he cannot improve his bat, his defense is too poor to play every day, leaving the majority of playing time to Gerardo Parra. A direct opposite of Kubel, Parra provides very good defense and little power. If he can sustain a high BABIP, he will likely be the better player.
The middle infield has the most question marks, with injuries and sustained poor performance casting doubt. Stephen Drew looks to recover from a broken ankle after struggling at the plate before the injury. If he doesn't lower his K rate or regain the power, he will not be much more than an average player. Aaron Hill came over in the swap of underperforming second basemen, with Arizona giving up Kelly Johnson. Hill did well in September with Arizona, but his past two seasons have been poor, not walking much and posting low BABIPs due to flyball tendencies. His power left him last year, which is really concerning for a flyball hitter. John McDonald and Willie Bloomquist return to spell the two.
Paul Goldschmidt jumped from AA to the majors, providing major pop and many whiffs at first base. He put up monster numbers in the minors, but he was usually a bit old for the league and his strikeouts were not as high. If he can get his K rate down to 25%, he can provide a lot of offensive value. A career journeyman, Ryan Roberts broke out at age 30, providing over 3 WAR with a good all-around game. I doubt he can do much better, but he should keep up average production. Lyle Overbay and Geoff Blum are back, though playing time may get scarce. Miguel Montero has average plate discipline and good power, which is quite valuable for a catcher. If he can start 120+ games again, he should provide about 4 WAR. Henry Blanco returns after, by far, his best offensive season of his career in limited time.
The starting pitching in 2011 was the biggest surprise of the team. Ian Kennedy improved the most, posting a 2.88 ERA and winning 21 games. However, his 3.22 FIP and 3.44 SIERA show regression is likely on the horizon. His flyball skillset does not translate well in Phoenix, a very good launching pad. Daniel Hudson saw a drop in strikeouts, but that was offset by some home run luck, leading to a similar FIP to Kennedy. If his K rate goes back up, as his whiff rate suggests, that should put him on the same level as Kennedy. Trevor Cahill comes over from Oakland, providing a lot of groundballs to the staff. His other skills are very average, so don't expect an ERA much below 4.00. Joe Saunders has overperformed his FIP three of the last four seasons, but a pitcher who doesn't strike out many without a significant other skill is likely to have a 4.50 ERA. Josh Collmenter and his straight overhand delivery burst onto the scene, though his 3.38 ERA is unlikely to be repeated. As an extreme flyball pitcher, his BABIP allowed will be lower, but .255 is still lower than expected, and his HR/FB% was lower than one would expect at Chase Field. Expect him to be much closer to a 4.00 ERA this season. Other possible starters include Wade Miley and last year's #1 pick Trevor Bauer.
The bullpen is headed by J.J. Putz, who posted K/BB rates reminiscent of '06-'07. If he can stay relatively healthy, he is a top 10 closer in the game. David Hernandez also did very well in his first full season in the 'pen. While his control is subpar and allows a ton of flyballs, he misses enough bats to remain effective. Takashi Saito, Craig Breslow, and Brad Ziegler are all also likely to see important innings throughout the season.
2011 was a great season for Arizona, and it seems likely that the success can continue. While the starting staff may not be as good, the offense should not be any worse, and the team is young enough to not worry about aging regression for the most part. The Giants have better pitching, but the Diamondbacks offense should carry them to another division title.