The Rockies' rotation, once so stable and full of homegrown pitchers, is in a weird, transitional state of flux. Jeff Francis and Aaron Cook are long gone, and Ubaldo Jimenez, the team's ace since his first full season in 2008, is a Cleveland Indian after last summer's trade. Some of their veterans remain, but to fill the last few spots in the rotation, Colorado has acquired pitchers left and right. The plan seems to be to throw them all against the wall and see who sticks -- most likely in order to keep their top pitching prospects in the minors longer -- but the kind of pitcher they have stocked up on goes against the idea of nearly every successful starter the Rockies have employed.
To understand the why, a little explanation is in order. This isn't new knowledge, but Coors Field is an extreme hitter's park. In 1999, the Rockies ranked second in the National League and fourth in the majors in runs scored, but after adjusting for park, their offense was actually 14 percent below-average (86 OPS+). The introduction of a humidor, in which baseballs were stored in order to counteract the dry, thin air of Denver, slowed offense considerably. But even with that, Coors remains baseballs most inflated offensive environment, as extreme and friendly towards hitters as Petco Park is to pitchers.
The humidor helped counteract homers to a degree, but there is only so much it can accomplish a mile above sea level. According to Statcorner, which uses three-year park factors broken down into component stats like singles, doubles, etc., lefties hit homers 13 percent more than average at Coors, while right-handers go yard 17 percent more often. Even Coors' post-humidor state puts the park in the same territory as the Ballpark in Arlington in terms of the long ball.
It's not just homers that the pitchers need to fear in Colorado, though. The ballpark's dimensions make outfielders cover a ton of space. Because of this, batting average on balls in play is higher than league average. In 2011, the league average BABIP was .295, but Coors was at .312. In 2010, the league sat at .297, Coors at .326. 2009, .299 and .317. These are all post-humidor years, too.
This kind of environmental disadvantage is why James Click, formerly of Baseball Prospectus but currently the Director of Research and Development for the Rays, introduced a park-adjusted Defensive Efficiency (PADE) back in 2003. The Rockies, who were close to the bottom via standard Defensive Efficiency, all of a sudden looked to be near league-average after park adjustments. That's a major difference, and a reminder of how important context can be when evaluating a team.
To bring it back to the Rockies' off-season, context seems to be what's missing in these moves. In this massive ballpark, where the combination of dimensions and thin, dry air is out to hinder pitching and help hitting, there are two routes to go that can make for decent pitching: the ability to strike hitters out, and a tendency to induce groundballs. Groundballs go for hits more often than flyballs in terms of BABIP, but are less problematic at altitude, and aren't going to accidentally become a home run. Missing bats means the defense doesn't even need to get involved, avoiding the pitfalls of the park completely.
The Rockies have basically avoided both strikeouts and groundballs this winter. Kevin Slowey was the first "Huh?" acquisition. While Slowey might be a decent enough starting pitcher in the right environment -- he walks almost no one, helping to counteract his below-average punch out rate -- Coors is not the right place for a pitcher with a groundball-to-flyball ratio of 0.7 (league average is around 1.1 to 1.2). And, while it's tough to draw conclusions on BABIP from just 532 innings, Slowey has a career BABIP of .310 -- not that surprising for someone who lives in the strike zone and relies on contact, and potentially problematic in a park where BABIP is inflated.
On Monday, the Rockies traded Seth Smith to the Athletics for Josh Outman and Guillermo Moscoso. Moscoso has had some decent strikeout numbers in his minor league career, but looked to be more average in that regard in the high minors with the Rangers. He struck out just 5.2 per nine in 2011 with the Athletics over 128 innings, and, as if that weren't enough, induced groundballs just 27 percent of the time. He leaned just as extreme towards flyballs in the PCL, as well, and if you want to use Minor League Splits' numbers as a rough estimate, 2011 wasn't the first time he eschewed grounders for air balls, either.
In Outman's 151 MLB innings, he has also been an extreme flyball pitcher, but his minor league numbers are a little more all over the place. Still, it's unlikely he'll lean groundball, and he doesn't miss a ton of bats. At least he knows there will be issues.
The Rockies aren't stopping there, as they have offered a deal to 49-year-old Jamie Moyer. That's the same Moyer who has given up 1.3 homers per nine since 2006 in a hitter's park less extreme than Coors and the same Moyer who has a G/F ratio of 1.0 since 2002, with one season that ever so slightly leaned more groundball than flyball in that stretch. Moyer, who has struck out 5.3 batters per nine and relied almost entirely on his change-up and guile over the years, will now have to contend with a park that was built to destroy pitchers like him. It's just a minor league deal, so it's not as if he is guaranteed a job, but if not Moyer then it's going to be another flyball-oriented hurler in the role.
In the long run, these arms don't matter. They are acting as a bridge towards the pitchers who do: Drew Pomeranz, Tyler Chatwood, Alex White, and Juan Nicasio. It's just disturbing in the short-term, if you're a Rockies fan, to see temporary bridges built with such a disregard for the environment they're placed in, especially after the team had the success they did with Jimenez, Cook, and present-day starters like Jorge de la Rosa and Jhoulys Chacin. In a division as winnable as the NL West, what appears to be a lack of effort to respecting context just might cost the Rockies in 2012.