The Ulsterman has spent his first few weeks at the Stadium of Light monitoring the squad he inherited from Steve Bruce and deciding whether he needs to strengthen it during the current window.
A significant upturn in results, coupled with James McClean's emergence as a genuine first-team player and Fraizer Campbell's imminent return from a 17-month injury lay-off, has lessened the need for O'Neill to ask owner and chairman Ellis Short to fund a spending mission.
The manager planned to sit down with Short this week to discuss the way forward, but as yet, it appears they have not drawn up any major recruitment plan for the remaining days of the window.
Asked if he would be happy to go with what he already has for the rest of the season, O'Neill said: "That's something I will monitor.
"It's the injuries that would cause you more concern - you can deal with suspensions, they are part and parcel of it, but that definitely causes you a concern.
"The truth is this here, that perhaps if we are wanting to try to compete, first of all you would like to be as healthy as possible and you would like to be as strong as possible."
O'Neill is no fan of the January rush for signings, which he believes leaves managers attempting to juggle budgeting requirements with the fear of long-term injuries.
He said: "I don't think anybody is a fan of it. January becomes a manic month.
"The problem with it is you realise that when you come to February 1, that's it all over, so whatever team you have assembled at that stage, that's it until the end of the season.
"If you get a spate of injuries in the first or second week of February, then you can't do anything about it, so from that viewpoint, it becomes a bit manic.
"Football clubs have tended to stay off it until the last possible moment and then suddenly in the last few days, there's a lot of movement.
"But most managers would be thinking along the same lines: what they are concerned about is not having the requisite number of players at your football club for the very, very important next few months."
O'Neill's relaxation about his squad is perhaps best illustrated in that he has allowed five of his youngsters - John Egan, Billy Knott, Jordan Cook, Louis Laing and Ryan Noble - go out on loan.
However, it is understood the Black Cats are continuing to monitor a series of potential targets.
