An important NL Central battle is on tap Friday, as the Pittsburgh Pirates open a three-game series against the St. Louis Cardinals at Busch Stadium. The Pirates are just 1 1/2 games ahead of the Cardinals in the division, but failed to increase that lead on Thursday, as they were denied a three-game sweep of the Milwaukee Brewers with Wednesday's 9-3 loss at Miller Park. Francisco Liriano was hammered in his three innings of work and allowed seven runs and seven hits. Andrew McCutchen homered and newcomer Marlon Byrd added three hits and an RBI for the Pirates, who had won five of seven games. Pittsburgh will also visit Texas on its current road trip and hopes A.J. Burnett can pitch the club back into the win column. Burnett is 7-9 with a 3.09 earned run average in 25 starts and threw seven innings of one-run ball in last Saturday's 7-1 win over the Cardinals. Burnett, a right-hander, is 8-5 with a 3.79 ERA in 16 career starts against the Cardinals. St. Louis, meanwhile, will kick off a nine-game homestand Friday versus the Pirates, Brewers and Mariners, and enters having lost six of eight games. In Thursday's 6-2 loss at Cincinnati in the finale of a four-game set, Lance Lynn was dealt the loss for giving up four runs in five innings. David Freese homered in the loss for the Cardinals, who currently lead the NL wild card race. Joe Kelly gets the start for St. Louis and is 7-3 with a 3.20 earned run average in 32 games this season. Kelly hasn't lost since June 5 and is 7-0 with a 1.72 ERA in his last nine starts. The Cardinals are 8-1 in that time. Kelly has faced the Pirates seven times (3 starts) in his career and is 2-2 with a 3.81 ERA. Pittsburgh is 10-6 against the Cardinals this season.