Keano had several battles with the former Arsenal ace, as a player for Manchester United.
Keane told the Sun, when they asked him to confirm his interest: “Not when I found out his wages!
“If I believe this player can give us something, I’m sure the board would back us. We’re always making enquiries about lots of players.
“How great is he? I don’t know. I don’t go down that road. I just know he was a bloody good player.
“He had good leadership skills, too. But not as good as mine!”
One of his famous battles with Vieira was before the two teams clashed at Highbury three years ago.
He said: “There is only one person to blame for that — Gary Neville. He started it and then went missing.
“Gary had a go at nobody. Someone just had a go at Gary coming in from the warm-up. So Gary told me.
“Gary was a team-mate and I thought it was out of order. I had to defend my team-mate. I’d do it again.
“You do not go around threatening people in the tunnel but you defend yourself, especially away from home if you are up against it.
“You don’t win games in the tunnel, though. You might lose them. We still had to go out and win. I think we won 4-2.
“They were great occasions against Arsenal. It was a battle, the tensions between the two teams, between the managers, the two clubs — brilliant! Absolutely brilliant!
“By God, you looked forward to those games.”
