News emanating from the Academy of Light today suggests that a whole host of youngsters are set to depart Wearside for good, as O'Neill seeks to trim the club of players who seemingly have no long-term future with the Black Cats.
The exodus, of course, began last week with the movement of Blair Adams to Coventry City. Now, however, O'Neill is keen to continue to encourage youngsters to ply their trade elsewhere.
Craig Lynch and Ryan Noble, two attacking players who have flirted with the first team in recent seasons, seem set to leave. Both were, according to the Sunderland Echo, wanted on loan by unnamed Dutch sides, but turned down those particular advances.
Lynch, however, is now supposedly being chased by League One side Sheffield United, and The Blades are keen to make the move a permanent one. While Noble may not be out of the exit door quite so quickly, it certainly seems that his days on Wearside are numbered. Neither has yet completed a move away from the club, but the signs are that it is merely a matter of time.
One man who won't be making any further impression at Sunderland is Roarie Deacon. Signed from Arsenal in the summer of 2011, Deacon's contract ran until the end of 2012 - the club have decided not to offer him an extension.
Elsewhere, James Armstrong has rejoined Steve Bruce, having moved on a free transfer to Hull City. Adam Reed, a regular midfield fixture for the Under 21s this season, is in talks with Portsmouth over a similar permanent move.
Blair Adams' move to Coventry last week had some observers wondering aloud the worth of the Academy of Light. The argument went that, if the club were not willing to give youngsters a chance, the state-of-the-art training facility was not worth its cost.
Yet, this is something of a kneejerk. In Jordan Henderson, the club's Academy managed to recoup £20m from one player. Martyn Waghorn joined Leicester City for a fee in the region of £3m. Grant Leadbitter offered the club vital service before moving to Middlesbrough for a decent cost. The worth of Jack Colback, a prominent first team member, cannot be understated either.
The truth of the matter is simply that, for whatever reasons, the current outgoing crop haven't proven themselves good enough to stay. Noble and Lynch, in particular, have flickered on and off the scene, but with each growing older - they are 21 and 20 respectively - both must do what they can in order to avoid their careers stagnating. If they do not feature in O'Neill's plans other than being used as backup when an injury crisis hits, it is only fair that they are given the chance to ply their trade elsewhere.
Despite the departures, a number of promising youngsters remain on Wearside and, presumably, in the manager's plans. Louis Laing and John Egan are the most high-profile of those, but the likes of Adam Mitchell and Jordan Laidler may well see this as an opportunity to push for a more prominent striking role.