The prize right-hander is in camp with the Nationals this spring. Doctors have said his recovery time from Tommy John surgery is 12 to 18 months.
The Nationals also claimed left-handed pitcher Lee Hyde off waivers from the Atlanta Braves on Wednesday. The 26-year-old Hyde was a combined 4-6 with eight saves and a 3.41 ERA last year in Triple-A and Double-A. He had Tommy John surgery in 2007.