The Magpies signed Darlow at a cut-price because they were willing to let him return to Forest for a year, but their short-term thinking may be costing them.
Although it would have been impossible to predict Newcastle's current injury crisis, their failure to plan for the worst case scenario is putting their season at threat.
With Tim Krul and Rob Elliot both injured, Darlow would surely have been next in-line to play between the sticks for Alan Pardew's men had he been at the club.
However, as there was no recall clause in his loan deal, Newcastle have been forced to throw the inexperienced Jak Alnwick in at the deep end and, at the moment, he is struggling to stay afloat.
The goalkeeper's error in the Capital One Cup last night, as he dropped a corner to allow Nabil Bentaleb to tap in, put his side on the back-foot and he looked uncertain throughout.
"If ever the cliche of goals changing games was relevant, this was it," Alwnick's manager Pardew said to Sky Sports. "I thought the game was pretty even, really. Jak makes a mistake on the cross and you can get away with that sometimes, if the defender clears it or strike hits it over the bar."
"But it goes in and that kind of summed up our night, really."
Alnwick was arguably at fault for one of Arsenal's four goals in their Premier League match at the weekend, too, and although it would be harsh to attribute the defeat to solely onto him his performance did not help.
The problem for the club is that they have little choice but to persist with him as the Premier League will not permit them to sign a more experienced goalkeeper on an emergency loan.
Newcastle plan to appeal this decision, after Alnwick picked up a knock to the shoulder yesterday evening, but if it is rejected then an even more inexperienced candidate could have to start at the weekend.
Freddie Woodman is just 17-years-old, but he looks the obvious selection choice for Sunday's game, which just happens to be in the pressure-cooker of the North East derby.
The match is one which can be a nerve-wracking experience for even the most battle-hardened of performers, and Woodman's inclusion is unlikely to fill the side with confidence.
The whole scenario is made more frustrating given that Darlow is on their books, but he cannot represent them in times of crisis and, although Newcastle may have thought they had themselves a cheap deal in the summer, they will be wishing they paid the excess now.