Coors is the hardest park in which to get strikeouts.
This means more balls in play.
Clayton had more chances per inning in 2004 playing at Coors but that was casued by more balls in play and his chances per inning adjusted for the pitching staff strikeout rating probably went down. In additon his ZONE rating was down.

Balls are hit 10% faster and farther at one mile of altitude which might explain why ZONE ratings are negatively impacted at Coors.

Mike Bravard (PB)