Morton building toward Altoona rehab start

Karstens also slated to pitch on Monday; McDonald still without timetable

Morton building toward Altoona rehab start

PITTSBURGH -- Charlie Morton was scheduled to throw 35 pitches off a mound on Monday afternoon, using all four of his pitches. If all goes well, the 29-year-old will likely make a rehab start for Double-A Altoona on Thursday, according to Pirates manager Clint Hurdle.

Morton, who underwent Tommy John surgery last June and is dealing with a shoulder issue as well, will likely throw 65 pitches in four innings for the Curve.

James McDonald, on the other hand, has no timetable for a return. Hurdle said the right-hander will not begin a throwing program until the soreness or tenderness in his shoulder is gone. The Pirates placed McDonald on the 15-day disabled list on May 7 -- retroactive to May 1 -- with discomfort in his right shoulder. The 28-year-old is 2-2 with a 5.76 ERA.

"McDonald is just still on hold," Hurdle said.

Right-hander Jeff Karstens was also set to make a rehab start for Class A Bradenton on Monday. Hurdle said Karstens will likely throw 50 pitches over three innings. Karstens began the season on the disabled list with a shoulder injury and threw 29 pitches in a two-inning rehab start in extended spring training on May 8.

Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. Steven Petrella is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.