"I had decommitted from Boise a while ago," Manu told Bronco Country. "It was just between me and the coaches. No one else knew."
Manu had gone silent to reporters and the media in the last couple of weeks, but opened up about his decision to play for Chris Petersen in Seattle.
"Me and Coach Pete had a decent relationship at Boise. The main coach I had a coach relationship with was (linebacker) coach (Bob) Gregory. We talked a lot and when he moved to Washington I told him, 'Thanks for getting to know me at Boise.' He told me he was going to keep recruiting me. That helped a lot."
Manu also stated the NCAA's new governing structure played a huge role in his decision.
"Being able to play for a national championship is important," he said. "That new rule the NCAA passed giving all the power to the Power-5 was huge. It was a big part of my decision."
With his decision made, Manu is looking forward to his senior season with the Rams.
"It’s still setting in right now. Growing up and watching USC, Oregon, Washington, Utah, it’s been a dream of mine to play with them and against them," Manu said. "Now that I’m committed to a Pac-12 school, it’s a dream come true. It’s nice getting it out of the way before the season starts. Now I can focus on getting back to the state title game."