The continent's premier international football competition begins on 5 January and, under FIFA rules, the South Korean Football Association are able to call up their players up to 15 days before the tournament.
Chronicle Live claims that Newcastle are currently in negotiations with the South Korean football authorities regarding when Ki needs to be released.
However, should the 29-year-old leave England 15 days before the international competition, Saturday's Premier League encounter against Fulham at St James' Park could be his final Magpies appearance for a number of weeks.
With the final not taking place until February 1, Ki could miss up to eight Premier League matches plus the FA Cup third-round tie with Blackburn Rovers if the Taeguk Warriors have a fruitful campaign.
Ki is reported by Chronicle Live as saying he doesn't know just yet when he will depart for the Asian Cup and isn't even sure whether he will lose his first-team place upon his return.
"And then, of course I feel a little sorry for the team, as they’re in the middle of the season, but at least we’re in good shape," he added.
Some Newcastle fans have reacted to Ki's announcement on Twitter:
Ki will be a massive loss. Jonjo will have to step up— Dan Bell (@DanielB00955238) December 16, 2018
That's disappointing, he's been great for us.— Toonfan (@ataylor1892) December 16, 2018
Not good— neilB (@neilTheMagpie) December 16, 2018
This is absolutely infuriating.— Burnsie #NUFC (@Optimistoon) December 16, 2018
Reading the quotes from Ki, it makes it even worse.
The team isn't in "good shape" at all.
We're 4 points from being relegated as it stands.
With Shelvey injured this is sheer lunacy to not try and persuade him not to go.
We pay his wage not them, he should be told he’s not going— Les (@LesAnderz79) December 16, 2018
Don't know is why he's going. Should be offering him money not to!— Bri (@Bri2889) December 16, 2018
Ki started just two Newcastle matches during the opening three months of the Premier League campaign but has since won a first-team place, with eight league starts made so far (Transfermarkt).
Have something to tell us about this article?