"They have tried to get a forward who could supplement their strikers," Stapleton told Sky Sports News.
"It will take a bit of pressure off van Nistelrooy, who needs a few breaks to maintain the peak of his form. He is a goal scorer, he can hold the ball up and he has got good pace. He can play a number of positions; he can play in on the wing, in the hole behind a striker or alongside a striker."
"Players who play for United have to be special. Without a doubt he is potentially a great signing for United. With all the ingredients he has got and the team he will be playing in there is a lot to come from him and he is only 25 years of age."
Ex-United midfielder Micky Thomas was excited by the Saha signing as he felt the Frenchman was exactly the right sort of player to fit into Sir Alex Ferguson's game plan.
"With his pace and goal scoring ability this season it is a lift," Thomas told the Press Association.
"When Saha played at Manchester [on his Premier League debut for Fulham] he destroyed Jaap Stam, who was highly-rated then ,yet Saha took him to the cleaners. It is important to have pace in the Premier League and if he can score in an average team he will get lots more opportunities for United."
"I think 4-5-1 is the formation to play in Europe - that is the formation Ferguson wants to play - and Saha can fit into that."