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05/09/2013 8:14 PM ET

Morton to throw bullpen session Friday at Citi Field

NEW YORK -- The timing of a return to active duty in the big leagues by Pirates starter Charlie Morton may become a tad clearer this weekend when the club determines how his right shoulder responds to a Friday bullpen session at Citi Field. Morton, who underwent Tommy John surgery on his right elbow in June, experienced tightness in his shoulder after a rehab start.

His elbow is apparently no longer an issue, and the Pirates are confident the shoulder tightness is not a serious malady.

"We hope to resume his rehab after his bullpen," manager Clint Hurdle said. "You just keep moving forward and deal with what you have to deal with. Charlie was alarmed by what he felt [in his shoulder], and it was proper to shut him down, but he understands it's just something he has to push through."

Marty Noble is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.