After two recent knee operations, Coton has been forced to end his 10-year association with the Old Trafford outfit.
Although Coton is to remain on the United payroll until June, the 46-year-old is no longer able to carry out his duties, so academy coach Richard Hartis will step into the breach for the remainder of the campaign.
When reports of Coton's fitness problems began to emerge last month, it was suggested Van der Sar might be asked to combine a playing role with some coaching.
However, the 37-year-old, who recently signed a contract extension that will keep him with the Red Devils until 2009, wants to focus solely on his present career, a stance Ferguson wholeheartedly supports.
"Edwin will not be the man," the United manager told the Manchester Evening News.
"He wants to continue as a player, which is a sensible attitude.
"If he starts thinking now about what he is going to do when he is finished it will put a wedge between his goalkeeping performances and his mental approach to it all.
"That is the way we looked at it."