Aston Villa boss Martin O'Neill admits he's desperate for a new right-back.
He said: "If another signing doesn't materialise people can adjust. Olof Mellberg has played in that position in an accomplished fashion both for club and country.
"I will wait to see what happens in the next couple of days.
"I do want to strengthen the side and Zat has come in to improve the team.
"If he stays clear of serious injury he will be terrific for us.
"I've watched him for the last couple of years. When I was out of the game I watched a lot of Fulham games.
"I wouldn't be spending money if he wasn't a quality player. I mulled it over for some time and thought he was really worth going for."