Strasburg went 8-9 with a 3.00 ERA and 191 strikeouts last season. Strasburg gets the nod over Jordan Zimmermann, who made the All-Star team in 2013 and won 19 games.
In the past two opening day starts, Strasburg has allowed one run in 14 innings. He got the win last year against the Miami Marlins, pitching three-hit ball over seven innings.
"He has experience there. He's done it before," Williams said via The Washington Post. "And he's earned it. We spoke to Jordan. He's good with wherever and whenever he pitches. Opening Day is important. But the rest of the games are important, too."
The Nationals open their season March 31 against the New York Mets.