The former Aston Villa and Wolves man has found first-team football hard to come by since Ian Holloway's men won promotion to the Premier League and has been signed as cover for the injured Leon Barnett.
Manager Paul Lambert said: "With the severe injury to Leon we have brought Rob into the squad.
"He's got experience and he has seen and done it before after going up with Blackpool last season.
"He will be a big asset to us over the last 14 games of the season."
Edwards said: "Hopefully I can get cracking as soon as I can and help the lads in any way I can."
Source: PA
Source: PA