Jason LaCanfora from NFL.com has just announced via his Twitter account;
"SEA signing WR Mike Williams and FB Ryan Powdrell. Both played for Pete Carroll at USC. Williams was a top-10 bust"
Williams was reportedly doing very well the past few days during minicamp. More to come on this soon.
(Update:) Reggie Williams has also signed. Both Williams will compete for a WR spot. Both may make it with the best-case scenario, but likely only one will.