Chris Carpenter was given a vote of confidence in his return to the mound from a hamstring injury: He was named the Cardinals’ opening-day starter. In his first outing since March 1, when he injured his left hamstring, Carpenter gave up three runs and six hits in four innings in a 9-4 victory over the Tigers on Wednesday. “I feel fine right now and I’ll be ready for opening day,” Carpenter said. “All I need to do now is get my pitch count up and not hurt anything. It felt better as I went along.”