Detwiler missed most of the 2013 season because of back issues, but he was healthy enough to go to the instructional league toward the end of the season.
In his last start, if fact, Detwiler threw 90 pitches and was able to perform bunt plays without any problems.
"It went great. It couldn't have gone any better. His velocity was outstanding. He feels great. He has worked extremely hard during his rehab," Berry said about Detwiler. "In terms of where his heath is at, his back feels better than it ever has."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. Steve Gilbert contributed to this report. This story was not subject to the approval of Major League Baseball or its clubs.