The Ulsterman sent off some of his biggest names to do battle for their respective countries in the wake of yesterday's disappointing 1-1 draw with 10-man Norwich knowing they face a battle for Barclays Premier League survival on their return.
O'Neill's men have won none of their last seven league games and collected only three points in the process, with Wigan's controversial victory over neighbours Newcastle yesterday afternoon leaving them just four points clear of the drop zone.
Perhaps more worryingly, their next four fixtures pitch them into competition with leaders Manchester United, improving Chelsea, the Magpies and bogey side Everton.
The more pessimistic of fans are starting to worry about the source of the club's next point.
In the circumstances, O'Neill will hope for a clean bill of health after losing defender Carlos Cuellar to injury during the clash with the Canaries.
He said: "It will be a worry for us because we don't have that many to choose from. That's been a situation that has appeared all season, so I would obviously be concerned about the players going away.
"Some of them have two matches to play as well - a lot of them have - so I will just wait to see when they come back again.
"With Carlos Cuellar getting an injury, our concern is the players. We just need every able-bodied person around for the last eight games."
O'Neill himself continues to enjoy the support of owner and chairman Ellis Short, although the manager has publicly admitted that his squad lacks the necessary quality to prosper in the top-flight despite an investment of around £30million during the last two transfer windows.
That is not a situation which will change before the end of the current campaign and should the Black Cats retain their top-flight status - the 31 points they have collected so far should give them a platform to do so - there is sure to be a significant overhaul during the closed season.
The need for that became increasingly apparent yesterday as the current crop failed to take advantage of a game in which virtually everything went their way.
Things started badly when Wes Hoolahan headed the visitors into a 26th-minute lead, but their fortunes were to improve drastically before the break.
Norwich goalkeeper Mark Bunn was sent off just three minutes later after referee Chris Foy ruled that he had blocked Danny Graham's effort with his arm outside his penalty area.
The official came down on Sunderland's side once again when John O'Shea's through-ball struck Sebastien Bassong's arm inside the box and Craig Gardner gleefully rammed home the resulting penalty to level with five minutes of the first half remaining.
But despite the fact that the home side played with an extra man for more than an hour and had Steven Fletcher, Danny Graham, Stephane Sessegnon, Adam Johnson and later, James McClean and Connor Wickham at their disposal, they failed to trouble replacement keeper Lee Camp unduly.
O'Neill said: "The fact is that we didn't create clear-cut chances in the game.
"Yes, I know we had a number of balls go into the box that were cleared first time by their defenders when we should have been in there competing for that, but overall, that would be just the point, that we didn't create enough in the second half."
The Black Cats could also consider themselves fortunate that Mr Foy ruled that Danny Rose had blocked Russell Martin's 70th-minute cross with his arm inches outside rather than inside the penalty area with replays suggesting his interpretation had been generous.
Canaries boss Chris Hughton was delighted with the resilience his side showed despite their numerical disadvantage and was particularly pleased by the outlet given to them by 24-year-old winger Elliott Bennett.
He said: "That's why I left him on, Elliott. It was his first game for a while.
"I wanted to make some changes with 15 minutes to go, but because they were all digging in there, I wasn't quite sure who I wanted to make those changes.
"I thought about Elliott, but he just kept going. It was a really good 90-odd minutes from him."