Cardinals starter Edwin Jackson left in the sixth inning of Sunday night's 6-2 victory over the Rockies because of hamstring cramping. While facing Ty Wigginton with two runners on and one out, Jackson grabbed his hamstring on the follow through while falling behind 3-0 in the count. Jackson (2-1) has a 4.62 ERA in four starts over 25 1-3 innings with six homers since coming to St. Louis.