Jeff Lindquist started for the Huskies against Hawaii on Saturday as Miles was sidelined as punishment for his role in a fight on Feb. 2. Lindquist completed just 10 of 26 passes for 162 yards and a touchdown as Washington escaped with a 17-16 win.
Petersen's decision to start Miles following his suspension has been widely expected for weeks. Miles appeared in eight games in relief of Keith Price last season and completed 37 of 61 passes for 418 yards with four touchdowns and two interceptions.
He did not take part in any team activities following an altercation after the Super Bowl until being reinstated to the team on May 14.
At Pac-12 Media Days, Petersen said he was happy with how Miles responded after being suspended in February.
"He's done everything right, without question, or he wouldn't be with us," Petersen said. "Guys make mistakes, we all know that, certainly in that age group. We always say that the age group we're dealing with, for the most part, is the dumbest age group in America.
"It just happens to be so public. Guys make mistakes, but the important thing is that we learn from it," Petersen said.