Regression from key players was a huge story in the National League West in 2013. For instance, Dodgers outfielder Matt Kemp went back and forth between being injured and ineffective, and it took a monumental midseason run and bounce-back seasons from Hanley Ramirez and Juan Uribe, among others, to soften the blow. The entire Giants rotation, with the notable exception of Madison Bumgarner, basically fell off a cliff and the club finished with its worst record in six years as a result.
It can't always be predicted, but there are usually some red flags that indicate regression is in a player's future. Here are some of the more likely candidates to have a down year in the NL West.
Bronson Arroyo. A move to a pitcher's park probably would have suited the 37-year-old veteran well, but Arroyo instead chose to go to a place where he'll make half of his starts in a ballpark that is just as -- if not more -- favorable for hitters as the one he left behind in Cincinnati.
Arroyo mastered Great American Ball Park in 2013, striking out 88 batters and walking only 16 on his way to posting a 3.45 ERA in 122⅔ innings. However, the drier Arizona air could work against his mostly sinker-slider repertoire. And, as FanGraphs' Dave Cameron notes, Arroyo has proven himself quite susceptible against left-handed hitters and is entering a division that contains some very dangerous ones, unlike the NL Central.
Michael Cuddyer. It's not often that guys have career seasons at the age of 34, but Cuddyer did just that in 2013, posting a 137 OPS+ while leading the NL in batting average. Cuddyer is -- and, for the most part, has always been -- an above-average hitter, but a ridiculously high .382 batting average on balls in play made him an All-Star. That's 70 points higher than his career BABIP, and it points to serious regression for the grey-haired veteran.
It also doesn't help that injuries are starting to take their toll. Cuddyer missed 32 games a year ago after sitting out 61 in 2012. A move to first base might have gone a long way toward helping him avoid getting banged up, but the Rockies instead chose to sign Justin Morneau to fill that void, leaving Cuddyer to once again roam right field in Coors. In two seasons manning that spot in Denver, Cuddyer is a combined 21 runs below average, a figure that will probably be much worse at the end of the 2014 campaign.
Juan Uribe. Uribe has never been as good as he was in 426 plate appearances for the Dodgers last season. He posted a career-high .331 on-base percentage, slugged a respectable .438 and played terrific defense; Baseball-Reference had him at 22 runs above average at the hot corner. That came after two disastrous seasons in which Uribe managed a meager OPS+ of 54 while dealing with assorted injuries.
Sure, if Uribe stays healthy, he could still be a productive player for a Dodgers team that should enter the season as the heavy favorite to win the NL West. However, counting on a 34-year-old bad-bodied veteran with a career OPS+ of 85 to provide the type of production he did in 2013 would be foolish.
Eric Stults. It's hard to say that a guy who posted an ERA+ of 87 is going to regress even further, but comparing Stults' 2013 season to his major- and minor-league career provides some insight into how that's possible.
Stults didn't have great batted ball luck last year; he surrendered more than a hit per inning pitched and his BABIP-against was actually 10 points higher than his career average. However, Stults posted a strikeout-to-walk ratio of 3.28, something he'd never done before in the majors and barely even approached in the minors. And it's something he likely won't ever do again given the fact that he's entering his age 34 season and will be facing mostly improved offenses within the division.
Santiago Casilla. Casilla has always been prone to issuing walks, but in past years, he's been able to counter that with the ability to strike batters out at a decent rate. However, his strikeout-to-walk ratio dipped to 1.52 in 2013. It hadn't been that low since 2009, when he posted a 5.96 ERA with the Athletics.
Casilla isn't getting any younger; he's entering his age 33 season and his velocity is down more than three mph from where it was when he joined the Giants in 2010. His BABIP-against has gone up steadily over the past three seasons, and if it continues to rise, Casilla should start to see his ERA balloon as well.