On the surface, this one has all the makings of a potential streak-busting, letdown loss. The Rockies are playing with house money in the series with the Snakes having already won the first two games. They are going up against Arizona's erstwhile ace, while pitching a starter whose ERA suggests that he's been running a sale all season: opponents can get two games worth of scoring for the price of one.
So what reason for hope is there? Well for starters, Haren has been struggling somewhat this season, and the Diamondbacks have been as bad (5-9) in day games as the Rockies (11-6) have been good. Haren in particular has been shaky against left handed batters, which the Rockies have a bunch of, even with Seth Smith being held out for illness. A couple of the right handed bats that have found themselves in the lineup today, Ryan Spilborghs and Chris Iannetta, hit Haren pretty well. So that may leave the Rockies fate today in the hands of Ian Stewart and Troy Tulowitzki, who have been pretty well vexed by Haren in their careers to date. Tulo has a lifetime line of .226/.226/.452 off Haren, while Stewart is hitting .250/.286/.400 off the right hander.
As for Hammel, the best we can say is that he hasn't been as bad as he's looked or as the ERA would indicate. No that it's much consolation as the Rockies are 1-5 in his starts and we can't erase that, but Hammel's WAR value is actually just slightly behind the D-backs' Ian Kennedy and ahead of Josh Beckett, for example. Just as Ubaldo Jimenez's ERA is a near certainty to rise, Hammel's will be coming way down as the season wears on. It would be really nice if that process started today.