Keane, back in his native Ireland for a three-match mini-tour, reckons new boy McShane will add steel to his backline.
The Sunderland chief saw the 21-year-old come though the ranks at Old Trafford and said: "Paul is a born winner and will run through brick walls for you.
"I noticed him when I was at United and thought back then he would be a player, especially with some of the tackles flying in during training.
"He can't wait for the challenge and I am delighted to have him."
McShane's £1.5million arrival from West Brom was Keane's sixth summer signing.
But he has found life in the transfer market tough with the likes of David Nugent and Leighton Baines snubbing moves.
Chief Niall Quinn claims clubs like Portsmouth and West Ham are ruining it for the chasing pack by spending millions on average players and inflating the market.
Keane agrees and said: "The situation is going to get worse because more money will be pumped into the game. That's the way it is but we won't be going mad.
"We will spend the money but I won't be splashing out millions just for the sake of it. I am happy with what we have so far and there will be more to come."