Unbeaten Pirates rookie left-hander Zach Duke sprained his left ankle running the bases Tuesday night and was taken out after pitching two perfect innings against the St. Louis Cardinals. Duke (6-0, 1.81 ERA) singled off Jason Marquis to start the inning for his second career hit and moved up on Chris Duffy's single. But Duke was trapped off second on Nate McLouth's line drive that shortstop David Eckstein dropped. He was injured as he was tagged out scrambling back to the bag. Manager Lloyd McClendon, interviewed between innings on Fox Sports Net Pittsburgh's telecast, said Duke felt "something pop" in the ankle. Duke was immediately examined by team doctors, but there was no word how long he would be out.