WASHINGTON -- Right-hander Jordan Zimmermann was clearly the Nationals' top pitching prospect this season. He was a combined 10-4 with a 2.88 ERA for Class A Potomac and Double-A Harrisburg.

But the Nationals decided not to call Zimmermann up this month because of the amount of innings he threw and the biceps tendinitis he suffered in early August. Before the injury, the Nationals were thinking about putting Zimmermann in their rotation.

"We felt it was better that we handle him like we did with John Lannan, where we shut him down," general manager Jim Bowden said. "Jordan will be in big league camp. He has a chance to make our rotation out of Spring Training."

Zimmermann, 22, was the Nationals' second-round pick in the 2007 First-Year Player Draft.