The plan Pardew states the club is following makes far more sense than what others were calling for earlier in the summer.
He set out to improve the full back positions and signed three(all three of which can play in other positions). He is now waiting to see who are the best possible players left out of 25 man squads in the Leagues above before swooping. If he had swooped sooner for player A, he may have missed out on the much better player B who became available when left out of the 25 man squad on 29th August for example.