Mulder, who has been throwing to hitters since March 22, will pitch in an extended Spring Training game on Saturday. It will be his first game appearance of any kind since September of last season.
Starting with that March 22 throw, Mulder had been on an every-third-day plan. However, after his last session against hitters, on Monday, the plan changed. He threw a bullpen session on Wednesday, as a starter would typically do between games, and will throw Saturday on regular four days' rest.
From here out, Mulder should be on an every-fifth-day plan. He will continue to build up in extended spring before heading out on a Minor League rehabilitation assignment.
Mulder underwent surgery to repair damage in his rotator cuff in September of 2007. It was his second operation on the joint.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.