Starter Jeff Karstens (9-8, 3.32 ERA) who has been dealing with a minor shoulder injury, will return to the rotation and start against the St. Louis Cardinals on Tuesday night at PNC Park. Karstens skipped his recent start snd the Pirates may go with a six-man rotation the rest of the way, with Karstens, Ohlendorf, Morton, McDonald, Lincoln, and possibly Jeff Locke. Karstens has appeared in 28 games this season, making 24 starts and pitching 152 innings, a career high.