Many in the Nationals' organization believe right-hander Jordan Zimmermann has the potential to be a top starting pitcher in the Major Leagues. In his four starts with Class A Potomac while rehabbing from elbow reconstruction surgery, he has done nothing to prove otherwise.

Right-hander Jordan Zimmermann had his fourth rehab start on Wednesday. He pitched four shutout innings, allowing two hits and striking out four batters. He threw 47 pitches, 34 strikes.