"He's an important part of our plans. It's no coincidence he's played in every match this season."
On one occasion last season it led to a dismissal for a second bookable offence.
But Keane said: "I've never really been one for going down the road of imposing fines.
"There's no better feeling in the world than scoring a goal an sometimes it's hard to control your reaction in the heat of the moment. You just hope the penny drops."