Being in the rotation is nothing new to Roark, who won 15 games as a starter for Washington last season and had a 2.85 ERA.
"We have to have a starter one of those days. We can't argue with a -game winner. So he is going to get that turn," Williams said.
Roark lost his rotation spot this offseason after the Nationals signed Max Scherzer to a seven-year, $210 million contract. But Roark never complained, accepting his role as a reliever.
"He is the ultimate warrior, and he has done what we have asked him to do without comment, without complaint, without any change of attitude," Williams said. "He has taken the ball when he has been asked to take the ball. He will do the same when he gets his start."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.