Hansen wrote in the Telegraph: "Without a doubt he cost them three points (against Tottenham) and this is a crucial stage of the season where Sir Alex Ferguson needs to decide whether to stick with him or take him out the firing line.
"The result at White Hart Lane could prove a season defining moment and United cannot afford to be drawing games when they should be winning them.
"Sir Alex will be loath to drop him but he has got to make a decision now because this is crunch time and they are playing for big prizes. When your team is in the last 16 of the Champions League and competing for the title, the last position you want to be in is chopping and changing the goalkeeper.
"It cannot be allowed to continue because other teams are going to play on it. They will set up their approach to games to target the goalkeeper because De Gea undoubtedly has a frailty and a weakness when the ball is in the air and it has been proven time and time again."