ST. LOUIS -- Right-hander Jeff Karstens, on the disabled list with inflammation in his right shoulder since April 18, played catch on Monday at the club's Minor League facility in Bradenton, Fla.
He is still more than a month away from returning to the rotation.
The 29-year-old left his third start of the season, against Arizona on April 17, after one inning because of stiffness in the shoulder. He gave up three hits and two earned runs.
"He's going to continue throwing for a while," manager Clint Hurdle said. "He'll start with catch, go into a little distances and eventually move to some flat ground work -- and then to the mound."
Karstens went 9-9 with a 3.38 ERA last season, the best among Pittsburgh starters. He established career highs in wins, starts (26), strikeouts (96) and innings pitched (162 1/3).