Collymore wrote in his column for The People: "Instead of accepting top clubs are nicking his best players, the Gunners boss should be actively looking to take other top names from his rivals.
"Ferdinand is not playing for United because of a hamstring problem, and has a bit of a dodgy injury record from the past couple of years.
"But the Londoner will be sitting in his big Cheshire house knowing he has Chris Smalling, Nemanja Vidic and Phil Jones to compete with when he gets back. Is he going to play much?
"He could stay there for a couple more years and pick up trophies, but if I was Wenger Id go to United and ask the question.