Blazers have been depleted at guard with injuries to Scoot, Jrue, Tisse, Wesley, and Dame. They've been having to play a bunch of two-way guys and it's just not cutting it.
Meanwhile they have more centers than they need.
Williams III is on an expiring contract and the Warriors are looking to get some help at center where they are pretty weak at the moment. They are rumored to be after Williams and may be looking to shed some cap when he expires.
Not sure how bad they want him but here is a trade that actually works.