Sincilbanks
Vital Football Hero
Because it gives him a 50/50 chance of saving anything that is on target. The more steps he takes to one side or the other from his middle position reduces his odds on saving anything. The wall is a deterrent but can also act as a marker for the attacking player. As I have said before IF the attacker gets it in the top corner or as near to the post as possible and the keeper is one or two paces the other way from the centre of his goal it goes in. Hes got too much ground to make up and the ball is travelling too fast for him to do anything about it. You will see keepers making lots of saves and shots going high and wide but that is because the free kick taker hasn't got it exactly right.
I would love to see a team brave enough to not line up with a wall from a free kick 19-20 yadrs out. That would be interesting.
But that doesn't answer the question, just reinforces your belief that the keeper should be in the middle of the goal? If the keeper is in the middle of the goal, does he need a wall or not?