While Arroyo is having a good month of August (especially his last four outings), Coors Field has been a bit of a nightmare for him. In five starts there, he’s 1-2 with an ERA of 6.48 and a WHIP of 1.560 WHIP. In those starts, Arroyo has surrendered seven home runs.
The current Rockies roster owns a triple slash of .275/.320/.462 with 5 HR and 12 RBI when facing Arroyo. As you might guess, the lefty bat of Todd Helton (.360 BA, 2 HR, 5 RBI in 29 PA) has success whenever Arroyo is on the bump. A slight surprise is that Troy Tulowitzki, a righty, owns a .417 BA, 2 HR, 5 RBI in 13 PA against Arroyo.
As of this writing, Jorge De La Rosa is tied for second in the NL with 14 wins. Pitcher’s wins can be a fluky thing, but the fact a Rockies pitcher is there may appear to be even more of a fluke. Then you look at how De La Rosa has fared at Coors, you see why. He’s 8-1 with a 2.58 ERA and 1.335 WHIP in his 12 starts there.
And look at the difference in BAA when facing RHB and LHB. It’s no surprise that he has exhibited success in facing LHB, holding them to a .213 average. RHB are far more successful displaying a .276 BA when facing RHB.