Onwuzurike, considered one of the best defensive linemen in the country, racked up at least 30 tackles - six for loss - and two sacks in each of the last two seasons. He was headed to his senior campaign with the Huskies.
He's the second key starter from Washington's defense to declare for the draft, along with linebacker Joe Tryon.
The Pac-12 was one of two Power 5 conferences to postpone the fall football season in August due to COVID-19 concerns, but both have changed course. The Big Ten announced Wednesday that the new season will begin on the weekend of Oct. 24, while the Pac-12 has recently had positive developments regarding its return to play.