The Cardinals blew a 6-2 lead,falling 8-7 to the Pirates on Sunday. Pittsburgh tied it up 6-6 the sixth inning with a four-run rally. Tino Martinez’s throwing error allowed two runs to score. Aramis Ramirez drove in two more with a single off Dustin Hermanson. In the seventh inning, Abraham Nunez drove in the winning run with a sac fly and Kenny Lofton drove in another run. Dustin Hermanson was stuck with the loss. The Cardinals open a four-game series with the Astros today at Busch Stadium. St. Louis has lost five of eight games against Houston this season….Second baseman Fernando Vina left yesterday’s game with a strained hamstring. He could miss two weeks.