Diamondbacks Game Preview #112: 8/12 @ Rockies

You will not be surprised to hear that Coors Field is the National League park where the D-backs have had the highest ERA in their franchise history. At 5.69, it’s more than three-quarters of a run more than the next highest active venue, Busch Stadium’s 4.71. [Though a pair of defunct parks, old Yankee Stadium and Target Field in Minneapolis, both sit over 6.00, albeit only in a half-dozen games] It’s also close to a run and a half higher than the team’s overall ERA since 1998, giving you some idea of how tough it is to pitch in those conditions, even with a humidor. Yet it’s not universally so. Some Arizona pitchers - including one of this weekend’s starters - have done pretty well in Denver.

25 pitchers have thrown at least twenty innings for the D-backs there, and the median ERA among them is Robbie Ray’s 5.14. That’s a little lower than average, probably on the basis that if you’re good enough to survive long enough to pitch 20 innings in Coors Field, you’re likely doing something right. Of the AZ pitchers with fewer then 20 IP, there are five with an ERA in Coors above forty. Yes, four-oh. They go all the way up to J.D. Durbin’s sole outing for the team in this 2007 game, which left him with a career ERA as a D-back of 94.50. Though technical, Daniel Cabrera and Jake Diekman beat him in Coors, having allowed five and three runs respectively, without either retiring a batter in Denver.

At the other end, among those with a reasonable sample, the best high-altitude pitcher for the team is Rubby De La Rosa, who made three starts and held the Rockies to just five runs over his 20.1 innings of work, for a 2.21 ERA. Many in the top ten have a K:BB better than 5:1, which does support the idea that free passes are a bad idea in Coors. Counterpoint: Livan Hernandez, who struck out fewer than he walked (7:8), yet still had a 3.48 ERA over 20.2 innings here. Sinkerballers like Brandon Webb and Brad Ziegler are likely also no surprise to see with decent numbers in Coors: ground-balls tend to stay in the park! But #2 is Zac Gallen, with a 2.63 ERA over four starts and 24 innings. We’ll see tomorrow if that survives!