Williams has agreed to a three-year, $90 million contract extension with the Seahawks, Ian Rapoport of ESPN and NFL Network reports.
Spencer (undisclosed) reverted to injured reserve with the Commanders on Wednesday, per the NFL's official transaction log.
The Seahawks signed Jones to a contract Wednesday, Aaron Wilson of KPRC 2 Houston reports.
The Seahawks placed Clark (ankle) on injured reserve Tuesday, Brady Henderson of ESPN.com reports.
The Commanders signed Humphries to a one-year deal Tuesday, Ian Rapoport of ESPN and NFL Network reports.
The Seahawks placed Richman (leg) on injured reserve Tuesday, Brady Henderson of ESPN.com reports.
Jackson (hamstring) was placed on the Reserve/Injured list on Monday.
Basham was signed by the Commanders on Monday.
Commanders head coach Dan Quinn said that Sinnott is dealing with an oblique injury and is unlikely to play in Friday's preseason finale versus the Ravens, Nicki Jhabvala of The Athletic reports.