Clayton Kershaw is the ace of the Los Angeles Dodgers' staff, and Walker Buehler looks like an ace in training, but Hyun-Jin Ryu has been the team's most effective pitcher this season. Ryu's 1.27 ERA leads all major league starters, and he has allowed more than two runs in an outing just once -- Saturday against the Colorado Rockies. Ryu (9-1) gets another crack at hitter-friendly Coors Field when he takes the mound Friday night against Colorado in the second of a four-game weekend series.