The moves came a day after outside linebacker Jyles Tucker was placed on injured reserve.
Obiozor played in five games for Green Bay last season, primarily on special teams. The Cardinals claimed him off waivers in September. He was inactive for their first game this season, played in their second and spent the last two weeks on the practice squad.
San Diego routed the Cardinals 41-10 on Sunday.
Hughes has spent most of the past two seasons on the Chargers' 53-man roster, but has played in just one game.
The Chargers signed rookie linebacker Nate Triplett to the practice squad.
Copyright 2010 by The Associated Press